A question that does not seem to have a second intention, as there are no confusing elements. The statement concisely summarizes the description of pilocytic astrocytoma. The Rosenthal fibers may confuse us as they are not very specific, and make us think, for example, of pleomorphic xanthoastrocytoma in which they can also be found, but the cell morphology described (long and thin cytoplasmic processes, which are the ones that give the name "pilocytic") keeps us the first option as the correct one. We can find a good description of the entity, explaining what distinguishes it from other glial tumors in Practical Surgical Neuropathology. A Diagnostic Approach. A. Perry, D.J. Brat. p82-88. Churchill Livingstone Elsevier. 2010. (Philadephia).

A question that does not seem to have a second intention, as there are no confusing elements. The statement concisely summarizes the description of pilocytic astrocytoma. The Rosenthal fibers may confuse us as they are not very specific, and make us think, for example, of pleomorphic xanthoastrocytoma in which they can also be found, but the cell morphology described (long and thin cytoplasmic processes, which are the ones that give the name "pilocytic") [HIDDEN]. We can find a good description of the entity, explaining what distinguishes it from other glial tumors in Practical Surgical Neuropathology. A Diagnostic Approach. A. Perry, D.J. Brat. p82-88. Churchill Livingstone Elsevier. 2010. (Philadelphia).

A 20-year-old man with ataxia, headaches and solid-cystic mass in the right cerebellar hemisphere underwent surgery and a lesion was resected, histologically showing cells with long thin cytoplasmic processes, fascicular and microcystic pattern, numerous vessels and Rosenthal's fibers. The most probable anatomopathologic diagnosis is:

Hemorrhagic onset of cerebellar pilocytic astrocytoma in an adult: a case report and review of the literature implying a possible relation of degenerative vascular changes to the massive intratumoral hemorrhage.

Pilocytic astrocytoma (PA) is a low-grade astrocytic tumor arising predominantly during the first two decades of life. Hemorrhagic onset of PAs is uncommon, and the etiology of hemorrhage remains unclear. Here we report a case of hemorrhagic onset of cerebellar PA in a 29-year-old man who presented with a week-long history of headache and gait instability. Computed tomography and magnetic resonance imaging revealed a hemorrhagic tumor located in the right cerebellar hemisphere, and total resection was performed. Histological examination showed bipolar glial cell proliferation in a biphasic pattern in a compact area and a loose microcystic area with Rosenthal fibers and eosinophilic granular bodies, indicating PA. Prominent changes in tumor vasculature, including aggregation of sclerotic thick-walled and ectatic thin-walled vessels, was observed, and nodules of thrombi containing complex vascular proliferation suggesting recanalized thrombi formed in partially ruptured vessels were also found. Thus, rupture of these abnormal vessels appeared to be the cause of hemorrhage. Review of the literature revealed that age distribution of patients with hemorrhagic PAs tends to be older than that of patients with general PAs. These findings imply a possibility that degenerative changes in blood vessels in long-standing PAs might be related to the mechanisms of spontaneous intratumoral hemorrhage.

Primary cerebellar pilocytic astrocytoma with anaplastic features in a patient with neurofibromatosis type 1 - case report - .

A 70-year-old woman with neurofibromatosis type 1 (NF-1) presented with a primary cerebellar pilocytic astrocytoma (PA) with anaplastic features manifesting as worsening headache and ataxia. Magnetic resonance (MR) imaging on admission showed a diffusely enhanced solid mass in the left cerebellar hemisphere, although MR imaging showed no abnormalities 2 years before admission. Histological examination after gross total removal of the tumor exhibited a biphasic pattern with marked Rosenthal fibers, together with some malignant features including frequent mitoses and invasive growth pattern. The final diagnosis was PA with anaplastic features. Previous PA cases with mitotic activity and endothelial proliferation, and/or palisading necrosis have been classified as anaplastic PA (or PA with anaplastic features). In the present case, the tumor histology corresponded to this designation. The present case indicates that PAs with anaplastic features can occur in patients with NF-1.

[A case report of cerebellar pleomorphic xanthoastrocytoma].

Pleomorphic xanthoastrocytoma (PXA) is a type of astrocytic neoplasm, classified as WHO grade II, which mainly occurs supratentorially, and rarely infratentorially. We report an unusual case of PXA in the cerebellar vermis. A 36-year-old man presented with headache and gait disturbance. Magnetic resonance imaging and computed tomography demonstrated a mass lesion with cyst in the cerebellar vermis. The patient underwent total resection. Histological examination demonstrated nuclear and cytoplasmic pleomorphism, and xanthomatous change. Immunohistochemical examination demonstrated xanthomatous cells expressing glial fibrillary acidic protein. The histological diagnosis was PXA of the cerebellar vermis. The patient did not receive radiation therapy or chemotherapy after resection, and has experienced no recurrence for 12 months. This case suggests that PXA should be considered in the differential diagnosis of cystic lesion in the cerebellar vermis.

A rosette-forming glioneuronal tumor of the fourth ventricle: infratentorial form of dysembryoplastic neuroepithelial tumor?

Eleven cases of a distinctive tumor of the posterior fossa are described. The patients (age range 12-59 years) presented with headache and/or ataxia. Neuroimaging revealed a relatively discrete, focally enhancing mass(es) primarily involving the aqueduct, fourth ventricle, and cerebellar vermis. Hydrocephalus was present in seven cases, and two lesions were multicentric. In two cases a significant increase in tumor size was documented. Gross total or subtotal resections were achieved in 10 cases. One patient underwent biopsy alone and another received postoperative irradiation. Histologically, two components were identified in all cases. One consisted of neurocytes forming neurocytic and/or perivascular pseudorosettes in a fibrillary, partly microcystic matrix. The second, astrocytic component resembled pilocytic astrocytoma in 10 cases and consisted of fibrillated spindle cells with oval nuclei associated with occasional Rosenthal fibers, granular bodies, glomeruloid capillaries, and microcalcifications. Regionally, this component was more diffuse and patternless, consisting of sheets of round to oval, oligodendrocyte-like cells. Rare ganglion cells were seen in four cases. The rosettes were consistently synaptophysin and MAP-2 immunoreactive, whereas the spindle cells were positive for S-100 protein and glial fibrillary acidic protein. Overall, atypia was minimal; no mitoses were found, and Ki67 labeling indices were low. Ultrastructurally, the neurocytic cells featured processes containing microtubules and occasional dense core granules. Mature synapses were found in one of the four cases studied. Although the histologic features of this unique tumor superficially resemble those of dysembryoplastic neuroepithelial tumor, rosette formation by neuronal cells, the frequent presence of a pilocytic astrocytoma component, and the growing nature of the lesion argue against that diagnosis, as does occasional multifocality.

Rapid Recurrence and Anaplastic Transformation of a Pilocytic Astrocytoma in an Elderly Patient: Case Report and Review of the Literature.

Rapid recurrence of a pilocytic astrocytoma with anaplastic transformation is extremely rare. The case of an elderly patient with a cerebellar pilocytic astrocytoma with anaplastic transformation during short-term follow-up is reported. An 83-year-old woman presented initially with dizziness and a gait deviation to the right. Magnetic resonance imaging demonstrated a homogeneously enhanced mass in the right cerebellar hemisphere, and the tumor was subtotally removed by right suboccipital craniotomy. Histologic examination showed that the tumor cells contained eosinophilic cytoplasm and spindle-shaped processes with Rosenthal fibers and eosinophilic granular bodies, diagnosed as a typical pilocytic astrocytoma (PA). The MIB-1 index was <1%. The patient did not receive postoperative adjuvant radiation and chemotherapy. Two months after surgery, magnetic resonance imaging showed growth of the residual tumor adjacent to the fourth ventricle, causing obstructive hydrocephalus. She underwent surgery again, and the tumor was totally removed. Histologic findings showed mitotic cells and increased cellularity compared with the primary tumor, which was compatible with anaplastic transformation of PA with a MIB-1 index of 50%. Postoperatively, she was observed with best supportive care without postoperative adjuvant therapy. Nine months after the second operation, she died due to tonsillar herniation and obstructive hydrocephalus caused by a recurrent tumor. An autopsy was performed. It is extremely rare, as in the present case, that a cerebellar PA in an elderly patient recurs rapidly with anaplastic transformation, despite deferred postoperative adjuvant therapy including radiation and chemotherapy. A novel molecular-targeted therapy is needed for anaplastic PA showing aggressive biological behavior.

[Pilocytic astrocytoma of the cerebrum presenting in an elderly patient: a case report].

We report a case of pilocytic astrocytoma of the cerebrum presenting in an elderly patient. A 76-year-old man was admitted to our department due to the development of dysarthria. MRI showed a cystic mass with an enhanced small mural nodule in the left frontal lobe. At surgery, the cyst contents were aspirated, and the mural nodule was excised. Histological examination showed a pattern that is usually seen in pilocytic astrocytoma of the cerebellum, including loose and compact areas composed of pilocytic and stellate cells, a few eosinophilic granular bodies, but not Rosenthal fibers. Pilocytic astrocytoma is a common type of pediatric brain tumor that can arise within either the cerebellum or the hypothalamic/chiasmatic region, but rarely seen in the cerebral hemisphere at an advanced age. To our knowledge, only 45 cases of pilocytic astrocytoma of the cerebrum developing in an adult are reported. In those cases, the symptoms of the disease developed during the third decade of life. The onset at a most advanced age as in the present case is thought to be extremely rare.

Cerebellar pleomorphic xanthoastrocytoma in a patient with neurofibromatosis type 1: a case report and literature review.

Pleomorphic xanthoastrocytoma (PXA) is an uncommon tumor of young adults that typically occurs supratentorially. It is generally considered to be a low-grade, circumscribed tumor that when treated by surgical resection has a relatively favorable outcome. Cases of cerebellar PXA are rare, and those associated with neurofibromatosis type 1 (NF1) are even less common, with only 2 cases reported to date. We present herein a third case of PXA-NF1 with unusual features. A 33-year-old woman presented with a history of headache. Her medical and family history was significant for NF1. Brain MRI revealed a 3.4 cm ill-defined lesion with a gyriform enhancing pattern in the left cerebellum, superficially mimicking Lhermitte-Duclos disease. The patient underwent a gross total resection of the lesion and had an unremarkable postoperative course. While the lesion had histological features typical of "pure" PXA (WHO grade II) it had an unusual growth pattern with thickening of the superficial cerebellar folia and predominant leptomeningeal involvement. No BRAF, IDH-1, or IDH-2 mutation was identified. Three months after surgery, local recurrence was detected, and the patient was treated with radiation therapy. One year after the first surgery, she underwent surgical resection of the recurrent/residual tumor. Histologically, the recurrent tumor showed very similar features to the initially resected tumor, with no anaplastic features. Most cerebellar PXAs have an indolent clinical behavior as do most cerebral PXAs. Whether co-existence of NF1 was a factor in altering the clinical course and biologic behavior of this patient's tumor is currently unknown.

A 16-year-old male with a cerebellar mass.

A 16-year-old male presented to an emergency room after falling on his head while inebriated. The patient had only a history of recent fatigue and demonstrated no focal neurological deficit. MRI revealed a cystic and solid, enhancing midline cerebellar lesion. A suboccipital craniotomy was performed. Histologically, the mass showed large bizarre cells arranged in sheets with admixed small lymphocytes. The pleomorphic population had ample glassy eosinophilic cytoplasm and intranuclear inclusions. An infiltrating component resembling diffuse astrocytoma could be found in areas. Rosenthal fibers were particularly abundant in the areas of infiltrating glioma. Mitotic activity was very low, and necrosis was absent. Reticulin fibers between individual cells were focally abundant. Glial fibrillary acidic protein and vimentin were strongly expressed in many cells, while synaptophysin and neurofilament protein were not. Ki-67 showed a very low proliferation index. The pathologic diagnosis was pleomorphic xanthoastrocytoma (PXA) of the cerebellum. PXA is a diagnosis typically regarded as a superficial meningocerebral neoplasm. This case is one of sixteen cerebellar PXAs reported in the literature.

[A case of juvenile pilocytic astrocytoma with unusual neuroimaging features].

We present a case of cerebellar juvenile pilocytic astrocytoma(JPA) with unusual neuroimaging features. The patient was a 14-year-old male who suffered from chronic headaches for a couple of weeks. Plain craniogram showed a decalcification and bulging of the occipital bone. Computed tomography(CT) scans demonstrated low density multiple components with small calcifications in the right cerebellar hemisphere extending to the left. These calcifications were found at the margin of these multi-lobular components. Magnetic resonance imaging(MRI) revealed iso or low intensity on T1 weighted image, and slightly high intensity on T2 weighted image. The lesion indicated more heterogeneous and higher intensity than brain parenchyma on FLAIR imaging, and remarkable higher intensity than brain parenchyma with some small low intensity areas on diffusion weighted imaging. He underwent the complete resection except for the cranial tissue surrounding the pons. Histologic diagnosis was juvenile pilocytic astrocytoma, because of biphasic pattern of bipolar cells and a number of Rosenthal fibers. Generally JPA has sharp and smooth demarcated cysts with well-enhanced mural nodule. It was difficult to diagnose the presented tumor as JPA before operation, since its unusual neuroimaging resembled both dermoid and high grade gliomas.

Intra-cerebellar schwannoma with various degenerative changes: a case report and a systematic review.

Intra-cranial schwannomas account for less than 8% of brain tumors, among which more than 80% arise from the vestibular nerve. Intra-cerebellar schwannomas are extremely rare. Several cases have been previously reported but without remarkable degenerative changes on histology. A 61-year-old man presented with worsening disorientation, and an imaging study revealed a cystic lesion (6.5 cm in the largest diameter) in the left hemisphere of the cerebellum accompanied by a mural nodule (2.5 cm) located just inside the skull with enhancement and focal calcification, in addition to hydrocephalus. The lesion was more than 5 mm from the left acoustic nerve. The patient underwent gross total resection. Pathological examination revealed remarkable degenerative changes with various morphological features. Tumor cells were pleomorphic with rich cytoplasm containing numerous eosinophilic granules. Blood vessels and extracellular matrix showed remarkable hyalinization. Immunohistochemical staining revealed that the tumor cells were positive for S-100 protein and negative for Olig2. The tumor was diagnosed as a schwannoma with marked degenerative changes. The present case is discussed with reference to a systematic review of previous reports of intra-cerebellar schwannoma. Intra-cerebellar schwannoma should be included in the differential diagnosis of cystic lesions with heterogeneous histopathological morphology in the cerebellum.

[Cerebellar hemangioblastoma with marked pleomorphism: a case report].

We reported an extremely rare case of cerebellar hemangioblastoma with marked pleomorphism and reviewed the literature. A 68-year-old male presented with a one-month history of headache and vomiting. Neurological examination revealed right-sided dysmetria and truncal ataxia. Contrast-enhanced T1-weighted MR imaging revealed a heterogeneously enhancing tumor with solid and cystic components in the right cerebellum. The solid portion of the tumor was low intensity on diffusion-weighted imaging and low intensity on susceptibility-weighted imaging. 18F-fluorodeoxyglucose PET showed low uptake in the cerebellar tumor and the whole body examination was negative for malignancy. Vertebral angiogram demonstrated moderate tumor staining and no early filling veins. The patient underwent total removal of the tumor through suboccipital craniotomy. Microscopically, the solid tumor contained a cellular rich component consisting of stromal cells and a markedly pleomorphic component including atypical and multinucleated giant cells. The MIB-1 positive rate was 8.2%, which was slightly higher compared to that of hemangioblastomas. We observed strong staining for inhibin-α, aquaporin 1 and neuron specific enolase (NSE) in the tumor cells. PAX-2, cytokeratin and epithelial membrane antigen (EMA) were completely negative in the tumor cells, whereas the tumor cells demonstrated focal staining for CD10. The histological diagnosis was hemangioblastoma. Follow-up MR images showed no evidence of recurrent tumor 14 months after the resection. The study using a combination of immunohistochemical markers (e.g. inhibin-α, aquaporin 1 and PAX-2) is useful for differential diagnosis of hemangioblastoma from metastatic renal cell carcinoma.

[Clinicopathologic study of pilocytic astrocytoma].

To study clinicopathologic features, treatment and prognosis of pilocytic astrocytoma (PA). Histopathological, ultrastructural, immunohistochemical (EnVision method) and clinical features of 68 cases of PA were studied by microscopic investigation with correlation of clinical follow-up information when available. Thirty-five male patients and 33 female patients were studied. The patient's age ranged from 3 to 66 years (mean = 20.1 years). The mean time from symptom onset to surgery was 371 days (range, 3 days to 14 years). Cystic degeneration was noted in 41 cases (60.3%), and enhancement of the tumor was noted in 43 cases (87.8%). On postcontrast imaging examination there were 33 cases involving the cerebellum (48.5%). Total tumor excision was performed in 35 patients, subtotal tumor excision was performed in 31 patients, and the procedures of other 2 patients were not clear. Among 51 patients with follow-up information, 44 were alive, 7 had recurrent tumor, and 7 died. The post-operative survival ranged from 2 months to 124 months (mean survival = 48.1 months). Five years and ten years survival rates were 89%, respectively. Tumors with classic histopathology demonstrated biphasic pattern of growth, consisting of compact elongated bipolar astrocytes associated with rosenthal fibers, and less cellular areas of multipolar cells with granular bodies and microcyst. Some cases showed atypia of nuclei, and occasional mitoses. Involvement of subarachnoid space was seen in 17 cases. One case had anaplastic features. All cases showed diffuse positive staining for GFAP and low expression for Ki-67, except 1 anaplastic tumor with 10% Ki-67 indices. Tumors with subarachnoid space involvement showed positive reticular fiber staining and negative EMA staining. PA is a benign, WHO grade I tumor with favorable prognosis, and does not require radiotherapy after total resection. The tumor can be mistaken as higher-grade astrocytoma when involving the subarachnoid space, and with cytological atypia, leading to unnecessary radiotherapy after surgery. Recurrence rate is increased when only partial resection is achieved. The outcome for patients with brainstem tumor or anaplastic PA is poor.

Clear cell variants of intracranial tumors: meningioma and ependymoma.

We report two cases of rare histological types of intracranial clear cell tumor. Case 1: The tumor, on the left frontal convexity in a 64-year-old woman, consisted largely of polygonal cells with clear cytoplasm which were divided into lobules of uneven size by abundant fibrous connective tissue. Most of the tumor cells were immunopositive for epithelial membrane antigen and vimentin. Ultrastructurally, the tumor cells showed conspicuous interdigitations of their plasma membranes with frequent junctional complexes, and contained numerous glycogen granules in the cytoplasm and its processes. Occasionally, amianthoid collagen fibers were found in the fibrous stroma. Our diagnosis of this tumor was clear cell meningioma. Case 2: The tumor, in the right cerebellar hemisphere in a 64-year-old woman, consisted of round, clear cells with a honeycomb-like pattern. The tumor cells were positive for glial fibrillary acidic protein, vimentin and S-100 protein. Ultrastructurally, the tumor was composed of round cells arranged in a cell-to-cell pattern, and the adjacent cells often formed microrosettes containing microvilli in their lumina. There were scattered cells with accumulatios of glycogen granules in their cytoplasm. Our diagnosis of this tumor was clear cell ependymoma. From the light microscopic features of these tumors, it does not necessarily seem easy to discriminate them from other intracranial tumors composed of similar clear cells, such as oligodendroglioma, central neurocytoma, hemangioblastoma and metastic renal cell carcinoma. Ultrastructural examination is crucial in the identification of the clear cell variants of meningioma and ependymoma.

Pilomyxoid astrocytoma of the cerebellum with Williams syndrome: a case report.

A 3-year-old boy with Williams syndrome associated with supravalvular aortic stenosis was admitted to our hospital with disturbance of consciousness and a 2-month history of truncal ataxia. T1-weighted magnetic resonance imaging with contrast medium showed a heterogeneously enhanced tumor in the right cerebellum with severe hydrocephalus. The patient underwent tumor resection via suboccipital craniotomy. At the end of resection of the tumor, sudden cardiac arrest occurred after ST segment elevation. Despite immediate cardiopulmonary resuscitation, the patient died. Histological examination of the cerebellar tumor revealed that the tumor consisted of monomorphous bipolar spindle cells on a background of myxoid matrix, and angiocentric arrangement without Rosenthal fibers or eosinophilic granular body. The final diagnosis was pilomyxoid astrocytoma. This case of Williams syndrome with cerebellar pilomyxoid astrocytoma suggests the importance of investigation of the development of brain tumors and occurrence of intraoperative cardiac arrest associated with Williams syndrome.

Tanycytic ependymoma in association with neurofibromatosis type 2.

A rare case of tanycytic ependymoma associated with neurofibromatosis type 2 (NF2) is presented for the first time, with emphasis on its clinical course and histopathological features. A 30-year-old man had developed gait disturbance in his childhood, and harbored multiple tumors in spinal nerve roots, in the intradural extramedullary and intramedullary spinal cord. The spinal root tumor and intradural extramedullary tumor were histologically diagnosed as schwannoma and meningioma, respectively. Magnetic resonance imaging showed two intramedullary cystic lesions, one in the cervical and the other in the thoracic spine. Because his sensorimotor dysfunction in the lower extremities continued to worsen gradually, three of the multiple nodular tumors in the thoracic cystic lesion were removed. All three tumors were composed of eosinophilic piloid cells with modest nuclear pleomorphism. No Rosenthal fibers were found. A concentration of slender eosinophilic cellular processes surrounding the vascular wall was seen. Periodic acid Schiff and Masson trichrome-positive balloons were seen in the extracellular space. Detection of ependymal rosettes, although only few in number, led the diagnosis as a tanycytic ependymoma. Recognition of this ependymoma variant should be emphasized to avoid confusion with pilocytic astrocytoma or intramedullary schwannoma.

Pilocytic astrocytoma

Microscopic appearance Pilocytic astrocytomas are often cystic tumors, and, if solid, tend to be well-circumscribed. Under the microscope, the tumor is seen to be composed of bipolar cells with long "hair-like" GFAP-positive processes, giving the designation "pilocytic" (that is, made up of cells that look like fibers when viewed under a microscope). Some pilocytic astrocytomas may be more fibrillary and dense in composition. The presence of Rosenthal fibers, eosinophilic granular bodies, and microcysts can often be seen. Myxoid foci and oligodendroglioma-like cells may also be present, though these are not specific to pilocytic astrocytoma. Long-standing lesions may show hemosiderin-laden macrophages and calcifications.

Cerebellar Liponeurocytoma, an Unusual Tumor of the Central Nervous System--Ultrastructural Examination.

Cerebellar liponeurocytoma is a rare tumor of the central nervous system which shows neuronal and variable astrocytic differentiation, along with foci of lipomatous differentiation. It is usually located in the cerebellum, and may be mistaken for medulloblastoma with lipidized cells or lipomatous ependymoma. Histopathological examination, supplemented by immunohistochemistry and electron microscopy, is required to distinguish between these entities. This 35-year-old male presented with vomiting and headache for three months, followed by gait imbalance. Neurological examination showed positive cerebellar signs with ataxic gait. Magnetic resonance imaging showed a lesion measuring 4.4 cm× 4.3 cm× 3.9 cm involving the cerebellum. The patient underwent midline suboccipital craniotomy to excise the tumor. Histopathological examination showed a circumscribed, cellular tumor composed of round to polygonal cells with moderate cytoplasm and minimal pleomorphism. Clear intracytoplasmic vacuoles were seen within the tumor cells. These tumor cells were immunopositive for synaptophysin, NSE, and MAP-2, confirming their neurocytic origin. On ultrastructural examination, lipid vacuoles as well as dense-core neurosecretory granules were identified within these neurocytic cells, confirming the diagnosis of liponeurocytoma. No cilia, microvilli, or gap junctions were identified in the tumor cells, ruling out the possibility of lipomatous ependymoma. The differentiation of liponeurocytoma from its morphological mimics is imperative, as their treatment differs drastically. The role of electron microscopy is extremely important in this differential diagnosis.

Neurofibromatosis type 1-associated unusual pleomorphic astrocytoma displaying continual malignant progression.

Patients with neurofibromatosis type 1 (NF1) often have gliomas as a complication, most of which are benign pilocytic astrocytomas which have arisen in optic pathways. In the present case, a 17-year-old girl (at death) with stigmata of NF1, initially had a bulky tumor mass in the left thalamus, developing into the lateral ventricle, at 13 years of age. Partially resected tissue samples showed pleomorphic astrocytoma with abundant xanthoma cells and degenerative structures such as Rosenthal fibers (RF) and eosinophilic granular bodies. Fine eosinophilic granules identical to RF, both immunophenotypically and ultrastructurally, were also seen. The residual tumor was subtotally resected 6 months later, and the tumor histology was essentially similar as before, accompanying the regenerative structures; this was believed to be a good prognostic indicator. However, several anaplastic features such as mitosis, necrosis and vascular proliferation appeared even in areas rich in the regenerative structures. After a 2-year, disease-free interval, multiple tumor relapse occurred in June 1997. Partially resected tumor tissues were composed of monotonous small anaplastic cells with prominent proliferative activity. Surprisingly, the tumor cells had retained eosinophilic granules within the cell bodies. Postoperative chemotherapy with procarbazine, MCNU and vincristine (PCV) suppressed the residual tumor dramatically, but the regrowing tumor finally became uncontrollable, leading to the patient's death. TP53 mutation was not detected, while p27 immunopositivity was constantly high during malignant progression, suggesting acquisition of proliferative activity to overcome p53 and p27 inhibitory functions. A review of previously published reports failed to reveal any cases of this type.

Neurology_Adams

The cerebellar hemangioblastoma typically develops in the fourth decade and causes symptoms of ataxia and headache. On imaging studies, the lesions have a striking appearance of a cyst with a nodule contained in its wall, and angiography demonstrates the highly vascular nature of the nodule, which represents the actual neoplasm (see Fig. 30-13). The other identifying features of the disease, retinal hemangiomas, are smaller but indistinguishable histologically from the craniospinal ones. They are multiple and bilateral, usually appearing earlier than the cerebellar lesions but remaining asymptomatic until they become extensive (retinal detachment is one feature). Their diagnosis is made by funduscopy, by which a large feeding vessel leading to an irregularly shaped ovoid tumor in the retina can usually be appreciated. Imaging studies of the cranium that use dye enhancement will reveal them as well.

Pleomorphic xanthoastrocytoma arising from the suprasellar region: A report of two cases.

Pleomorphic xanthoastrocytoma (PXA) is a rare astrocytic neoplasm that usually arises in children and young adults. Typically, lesions of PXA are superficially located in the cerebral hemispheres. Herein, we report two extremely rare patients with PXA arising from suprasellar regions. One of the patients is a 29-year-old man admitted to our hospital with a history of progressive headache for 1month. The patient's brain MRI revealed a large tumor arising from the suprasellar cistern of the third ventricle. The second patient, a 52-year-old woman, presented with progressive dizziness and visual disturbance that had developed over the course of 1year. The MRI revealed a well-enhanced suprasellar solid mass measuring 1.4×1.2×1.4cm. Both patients underwent surgical removal of their tumors, and both patients showed similar microscopic structures and immunohistochemical phenotypes: the tumor cells were pleomorphic with mixtures of spindle-shaped, and multinuclear giant cells. In addition, eosinophilic granular bodies and xanthomatous cells were seen on section. Immunohistochemistry was positive for GFAP, S-100, and CD34, and was negative for IDH 1, CK, and Syn. The Ki-67 proliferation index was less than 1%. Silver impregnation revealed reticulin fibers surrounding the individual tumor cells, and small cell groups. Based on these findings, the two patients were diagnosed with PXA in the suprasellar region. To date, only five such patients have been reported in the literature. PXA should be included in the differential diagnosis for tumors arising in the sellar region.

Delayed occurrence of cerebellar pleomorphic xanthoastrocytoma after supratentorial pleomorphic xanthoastrocytoma removal. Case report.

The authors report the case of a 36-year-old woman who underwent gross total resection of a right cerebellar pleomorphic xanthoastrocytoma with atypical features. She had undergone surgery 16 years previously for what was thought to be a right frontal glioblastoma multiforme. In retrospect, based on the histopathology and the clinical course, both lesions were considered to represent atypical variants of pleomorphic xanthoastrocytoma. This report examines the histological and clinical characteristics of this posterior fossa lesion, which exhibited histologically malignant features but has run a relatively indolent course.

[Immunohistochemical study is helpful for the diagnosis of cerebellar clear cell ependymoma with atypical radiological findings--case report].

A 67-year-old male presented with a clear cell ependymoma with symptoms of ataxic gait and dizziness. Magnetic resonance imaging showed a ring enhanced and circumscribed mass lesion with some cysts in the left cerebellar hemisphere, and the vertebral artery angiogram showed the vascurality of the tumor fed by both the left posterior inferior cerebellar artery and the left superior cerebellar artery mainly. They demonstrated suspicious finding of metastatic tumor, glioblastoma, or cystic meningioma. Surgery via the left suboccipital approach revealed a whitish and solid tumor, which was demarcated from the cerebellar parenchyma and had no continuity with the 4th ventricle. Total resection of the tumor was successfully performed. The hematoxilyn-eosin staining of the surgical specimen was similar to hemangioblastoma or oligodendroglioma, however, immunohistochemical findings for glial fibrillary acidic protein, vimentin, epithelial membrane antigen, and factor VIII were compatible with clear cell ependymoma. The patient's postoperative course was uneventful, and his symptoms improved. Clear cell ependymoma is known as a variant of ependymoma, which is usually located at the foramen of Monro. We think that the immunohistochemical study is highly helpful for the diagnosis of the cerebellar tumor with atypical presentation such as our case.

WHO classification of tumours of the central nervous system

1.4.2 High-grade astrocytoma with piloid features 1.4.3 Pleomorphic xanthoastrocytoma 1.4.4 Subependymal giant cell astrocytoma 1.4.5 Chordoid glioma 1.4.6 Astroblastoma, MN1-altered 1.5 Glioneuronal and neuronal tumours 1.5.1 Ganglioglioma 1.5.2 Desmoplastic infantile ganglioglioma / desmoplastic infantile astrocytoma 1.5.3 Dysembryoplastic neuroepithelial tumor 1.5.4 Diffuse glioneuronal tumor with oligodendroglioma-like features and nuclear clusters 1.5.5 Papillary glioneuronal tumor 1.5.6 Rosette-forming glioneuronal tumor 1.5.7 Myxoid glioneuronal tumor 1.5.8 Diffuse leptomeningeal glioneuronal tumor 1.5.9 Gangliocytoma 1.5.10 Multinodular and vacuolating neuronal tumor 1.5.11 Dysplastic cerebellar gangliocytoma (Lhermitte-Duclos disease) 1.5.12 Central neurocytoma 1.5.13 Extraventricular neurocytoma 1.5.14 Cerebellar liponeurocytoma 1.6 Ependymal tumours 1.6.1 Supratentorial ependymoma 1.6.1.1 Supratentorial ependymoma, ZFTA fusion-positive

[Cerebellar ganglioglioma: a case report].

A case of cerebellar ganglioglioma is reported. A 22-year-old female was admitted to the Kurume University Hospital on August 19, 1985, suffering from headache, vomiting and gait disturbance. On admission, neurological examination revealed staggering gait and the right cerebellar ataxia showing dysmetria and dysdiadochokinesis. Mild choked disc in the right fundus was also noted. Plain CT scan showed the low-density area involving the right cerebellar hemisphere and the part of the vermis with internal hydrocephalus. Enhanced CT scan showed the high-density area adjacent to the low-density area suggesting a mural nodule. A vertebral angiogram in the arterial phase showed an expansive lesion in the posterior fossa and the tumor stain, which was also visualized in the venous phase. An emergency suboccipital craniectomy was then performed. With opening the tense dura mater, the cyst formation was noted and 30 ml of xanthochromic fluid was then aspirated. A well demarcated mural nodule was noted in the lateral wall of the cyst. The nodule was then extirpated in toto. The hypertrophy of the cerebellar cortex was not observed. Histologically, the tumor was consisted of nerve fiber, glial fiber and neuronal cells. Its architecture was differed distinctly from that of hamartomatous diffuse hypertrophy of the cerebellar cortex (Lhermitte-Duclos' disease). Immunohistochemically, the neuronal cells revealed positive staining for NSE and S-100, and the glial cells displayed positive staining for GFAP, S-100. The authors reviewed previously reported eleven cases of cerebellar ganglioglioma including the present case. These results showed that cerebellar gangliogliomas have some characteristic clinical features among general intracranial gangliogliomas.(ABSTRACT TRUNCATED AT 250 WORDS)

Pilocytic astrocytoma: a retrospective study of 32 cases.

Pilocytic astrocytoma (PA) is a neoplasia which is considered as a grade I astrocytoma by the World Health Organization (WHO). Its most common location is the cerebellum and it develops during the first two decades of life. Prognosis is mostly excellent if gross-total resection can be achieved, with 10-year survival rates of up to 95%. In rare cases, however, the patient has a bad outcome. Our aims were to retrospectively describe the clinicopathological features of 32 PAs, and identify factors that may be associated with aggressive behavior. The study included 21 males and 11 females with a median age of 10.5 years. Tumors demonstrated predilection for infratentorial location (74.9%), especially the cerebellum (59.3%), followed by cerebral ventricles (15.6%), supratentorial location (12.5%) and optic pathway (3.12%). Gross total resection was achieved in 14 tumors only. On histopathology, moderate cellularity (68.7%), microcystic changes (71.9%), Rosenthal fibers (62.5%) and eosinophilic granular bodies (53.2%) were present in the majority of cases. Atypia was present in 62.5% of cases, while endothelial proliferation and necrosis was noted in 3 and 2 cases, respectively. Median follow-up for all patients was 24 months. Four patients died in the postoperative period, one of whom was 62-year-old men and two others had brainstem location or invasion. Recurrence was observed in a 56-year-old patient whom first tumor was locally invasive. The patient died after the second surgery and anaplastic features was found in the recurrent tumor without previous radiotherapy. PA is a benign tumor, but some clinicopathological factors, such as partial resection, brainstem location and adult age have a worse prognosis.

"Integrated diagnosis" of pilocytic astrocytoma: Molecular diagnostic procedure for an unusual case.

A 24 year-old female presented with a mass lesion in the right temporal lobe. This case was difficult to diagnose using histological and immunological methods and therefore molecular analyses were applied to provide a definitive diagnosis. The tumor was well-demarcated, partially cystic, and irregularly-enhanced on gadolinium-enhanced T1-weighted magnetic resonance images. Pathologically, a large part of the tumor consisted of cells with fine cytoplasmic processes on a myxoid and mucinous background. Cells formed a microcystic structure around the mucinous tissue. Numerous eosinophilic granular bodies, but not Rosenthal fibers, were present. The solid and compact regions of the tumor were composed of fasciculation of dense fibrous glial tissues and occasional multinucleated giant cells. Tumor cells and their fragmented cytoplasmic processes were positively stained with GFAP, while eosinophilic granular bodies were both positive and negative. Xanthomatous changes were not detected and the reticulin fibers were restricted to vascular tissues. The MIB1 index was scored as approximately 10%. In molecular analyses of BRAF, the KIAA1549-BRAF (K16-B9) fusion gene was detected in all tumor regions, whereas BRAF V600E mutation was not detected by either conventional Sanger sequencing or the Eprobe-PCR method. Based on the results of the molecular analyses, this case was diagnosed as pilocytic astrocytoma.

1. Gliomas, glioneuronal tumors, and neuronal tumours 1.1 Adult-type diffuse gliomas 1.1.1 Astrocytoma, IDH-mutant 1.1.2 Oligodendroglioma, IDH-mutant, and 1p/19q-codeleted 1.1.3 Glioblastoma, IDH-wildtype 1.2 Pediatric-type diffuse low-grade gliomas 1.2.1 Diffuse astrocytoma, MYB- or MYBL1-altered 1.2.2 Angiocentric glioma 1.2.3 Polymorphous low-grade neuroepithelial tumor of the young (PLNTY) 1.2.4 Diffuse low-grade glioma, MAPK pathway-altered 1.3 Pediatric-type diffuse high-grade gliomas 1.3.1 Diffuse midline glioma, H3 K27-altered 1.3.2 Diffuse hemispheric glioma, H3 G34-mutant 1.3.3 Diffuse pediatric-type high-grade glioma, H3-wildtype and IDH-wildtype 1.3.4 Infant-type hemispheric glioma 1.4 Circumscribed astrocytic gliomas 1.4.1 Pilocytic astrocytoma 1.4.2 High-grade astrocytoma with piloid features 1.4.3 Pleomorphic xanthoastrocytoma 1.4.4 Subependymal giant cell astrocytoma 1.4.5 Chordoid glioma 1.4.6 Astroblastoma, MN1-altered

[Vertebral angiography of cerebellar hemangioblatoma -tumor stain, tumor circulation, CT and angiography in diagnosis(author's transl)].

Tumor "stain" and pathological tumor circulation were investigated mainly by cerebral angiography in 8 patients of cerebellar hemangioblastoma who were hospitalized in the Hokkaido University Hospital and considered to be suitable for this study. The results are presented with some speculation in this paper. (1) Tumor stain was found in all of the 8 cases. (2) Histologically all 8 cases were composed of endothelial cells with numerous vascular channels. The characteristic tumor "stain" in cerebellar hemangioblastoma was supposed to be closely related to the histologic features. (3) Review of the reports published on tumor stain indicates that tumor staining patterns have been classified into 3 to 5 types. Similar items were established in all the classifications. (4) The 8 cases were divided into 4 types: cystic type, cystic and solid type, solid type, and multiple type based on macroscopic natures of the tumor. Tumor staining patterns in angiography were also tentatively classified into types 1 to 4 according to the natures of the tumor. (5) Concerning pathological tumor circulation, (a) the time of appearance of tumor "stain" was long; (b) early filling veins in the tumor were found in 4 of the 8 cases; (c) almost all feeding arteries had one or two branches; (d) arteries originating from meningeal vessels were enlarged in 2 cases and angiography of the external carotid artery was useful for their identification; and (3) draining veins were enlarged more markedly than feeding arteries and were mostly a single superficial vein. (6) CT was performed in 4 of the 8 cases. It was compared with vertebral angiography regarding diagnostic capability in consideration of the published reports. Vertebral angiography was superior to CT in (a) verification of the presence of multiple lesions in cerebellar hemangioblastoma and (b) differential diagnosis between cerebellar astrocytoma and hemangioblastoma.

Brain tumor

Specific types Anaplastic astrocytoma, Anaplastic oligodendroglioma, Astrocytoma, Central neurocytoma, Choroid plexus carcinoma, Choroid plexus papilloma, Choroid plexus tumor, Colloid cyst, Dysembryoplastic neuroepithelial tumour, Ependymal tumor, Fibrillary astrocytoma, Giant-cell glioblastoma, Glioblastoma multiforme, Gliomatosis cerebri, Gliosarcoma, Hemangiopericytoma, Medulloblastoma, Medulloepithelioma, Meningeal carcinomatosis, Neuroblastoma, Neurocytoma, Oligoastrocytoma, Oligodendroglioma, Optic nerve sheath meningioma, Pediatric ependymoma, Pilocytic astrocytoma, Pinealoblastoma, Pineocytoma, Pleomorphic anaplastic neuroblastoma, Pleomorphic xanthoastrocytoma, Primary central nervous system lymphoma, Sphenoid wing meningioma, Subependymal giant cell astrocytoma, Subependymoma, Trilateral retinoblastoma.

Large cystic cavernous angioma of the cerebellum mimicking pilocytic astrocytoma.

Cavernous angiomas are relatively rare vascular malformations. They are generally located supratentorially with a rare incidence in the cerebellum. Cavernous angiomas, accompanied by a large cyst, are very rare. We present a case of a cavernous angioma with the unusual MRI findings of a large cyst and a small mural nodule. The patient was a 48-year-old man who complained of a history of dizziness for several weeks. The neurologic examination in the neurosurgery clinic was without deficit. The cyst measured 4.7x4.0 cm and contained serous fluid with a nodular mass in the lower part of the cyst. The cystic wall and the solid mural nodule were completely removed through a midline suboccipital approach. Postoperatively, the patient remained neurologically intact. When a large cystic lesion is present in the cerebellum, preoperative radiological and intraoperative findings led to misdiagnosis. Therefore, a rare cystic angioma must be considered in the differential diagnosis of infratentorial cystic masses.

Cerebellar pilocytic astrocytomas with spontaneous intratumoral hemorrhage in adult.

Cerebellar pilocytic astrocytomas (PAs) are benign gliomas predominantly found in the pediatric population. Intracranial hemorrhages are extremely rare in initial presentations of cerebellar PAs. There are no reports in the medical literature of adult cerebellar PA cases presenting with intratumoral hemorrhage. We report 2 cases of adult cerebellar pilocytic astrocytomas with intratumoral hemorrhage. The first case is a 37-year-old woman presenting with severe headache, nausea, and vomitting. Computed tomography demonstrated an acute hemorrhage adjacent to the right cerebellar hemisphere and hydrocephalus. Magnetic resonance imaging (MRI) revealed a cerebellar vermian tumor with the hemorrhage as a mixed isointense area in the T2-weighted image, and as a mixed hyperintense area in the contrast-enhanced T1-weighted image. The second case is a 53-year-old man presenting with headache for 3 weeks. MRI revealed a cerebellar hemispheric tumor with the hemorrhage as a mixed hyperintense area. It had a cystic mass with a heterogeneous enhanced mural nodule in the gadolinium-enhanced T1-weighted image and a fluid-fluid level within the cyst in the T2-weighted image. Both of them underwent radical resections of their respective lesions. Histological examination of the specimens revealed typical astrocytoma, including a hemorrhagic portion. Both patients recovered postoperatively and continue to do well at present. The medical literature on hemorrhagic cerebellar PAs is also reviewed.

Massive Calcified Cerebellar Pilocytic Astrocytoma with Rapid Recurrence : A Rare Case.

Pilocytic astrocytomas (PAs) are World Heath Organization Grade I tumors and are most common in children. PA calcification is not a common finding and has been reported more frequently in the optic nerve, hypothalamic/thalamus and superficially located cerebral tumors. We present a cerebellar PA in a 3-year-old male patient with cystic components and massive calcification areas. The residual tumor grew rapidly after the first operation, and the patient was operated on again. A histopathological examination revealed polar spongioblastoma-like cells. Massive calcification is not a common feature in PAs and can lead to difficulties in radiological and pathological differential diagnoses.