The standard work-up for<unk>  includes: * Magnetic resonance imaging (MRI) of the brain and spine * Lumbar puncture to look for M1 disease * Computed tomography (CT) of chest and abdomen to check for a<unk>  * Bone marrow aspiration to check for bone<unk> s. Sometimes the physician will perform a stem cell transplant * Bone marrow biopsy * Bone scan The initial diagnosis of a<unk>  is made with a radiographic study (MRI or CT-). If CT was performed first, an MRI is usually performed as the images are often more detailed and may reveal previously undetected metastatic<unk> s in other locations of the brain. In addition, an MRI of the spine is usually performed. The<unk><unk>  often spreads to the spine.<unk>  is difficult to diagnose only from radiographic study; usually, a pathologist must perform a cytological or genetic analysis. Examination of the cerebrospinal fluid is important (CSF), as one-third of patients will have intracranial dissemination with involvement of the CSF. Large<unk>  cells, eccentricity of the nuclei, and prominent nucleoli are consistent findings. Usually only a minority of<unk>  biopsies have rhabdoid cells, making diagnosis more difficult. Increasingly it is recommended that a genetic analysis be performed on the brain<unk> , especially to find if a deletion in the INI1/hSNF5 gene is involved (appears to account for over 80% of the cases). The correct diagnosis of the<unk>  is critical to any protocol. Studies have shown that 8% to over 50% of<unk><unk> s are diagnosed incorrectly. Classification<unk>  may be related to malignant rhabdoid<unk>  (MRT), which occurs outside the CNS, usually in the kidney. The finding that<unk>  and MRT both have deletions of the INI1 gene indicates that rhabdoid<unk> s of the kidney and brain are at least closely related.<unk>  and MRT also have similar histology and similar clinical and demographic features. Moreover, 10–15% of MRT patients have simultaneous or subsequent brain<unk> s, many of which are secondary or primary MRT. Differential diagnosis The critical step in treatment planning is to determine the correct histology of the<unk> . Misidentification of the<unk>  histology can lead to errors in treatment and prognosis.<unk><unk> /rhaboid<unk>  closely resembles medulloblastoma, primitive neuroectodermal<unk> , choroid plexus carcinoma, and some kinds of germ cell<unk> . Because rhabdoid characteristics are not the only component of<unk> , some sections of an<unk>  may resemble other<unk> s. These characteristics may be present only in focal areas or may be less pronounced. Consideration of<unk>  when a medulloblastoma or PNET is suspected is important, particularly in a child under the age of one. Cytogenetic studies can assist in differentiating MB/PNETs from<unk> s. Some kinds of germ cell<unk> s secrete<unk>  markers AFP or bHCG;<unk> s do not. Appearance on radiologic exam<unk> s can occur at any sites within the CNS; however, about 60% are located in the posterior fossa or cerebellar area. The ASCO study showed 52% posterior fossa; 39% sPNET; 5% pineal; 2% spinal, and 2% multifocal. The<unk> s' appearance on CT and MRI are not specific, tending towards large size, calcifications, necrosis (tissue death), and hemorrhage (bleeding). Radiological studies alone cannot identify<unk> ; a pathologist almost always has to evaluate a brain tissue sample. The increased cellularity of the<unk>  may make the appearance on an uncontrasted CT to have increased attenuation. Solid parts of the<unk>  often enhance with contrast MRI finding on T1 and T2 weighted images are variable. Precontrast T2 weighted images may show an isosignal or slightly hypersignal. Solid components of the<unk>  may enhance with contrast, but not always. MRI studies appear to be more able to pick up metastatic foci in other intracranial locations, as well as intraspinal locations. Preoperative and follow-up studies are needed to detect metastatic disease.
Atypical teratoid rhabdoid tumor
Malignant rhabdoid tumour
Pediatric ependymoma
Neurothekeoma
Endodermal sinus tumor
Sialoblastoma
Ameloblastoma
Primitive neuroectodermal tumor