A Long-Term Survival Case of a Primary Malignant Intracerebral Nerve Sheath Tumor
A 13-year-old boy was hospitalized due to the headache on the right side of his head, which began 2 weeks ago and the vomiting, which began a week ago. The patient was alert and showed no neurologic abnormalities. There was no evidence of neurofibromatosis such as neurofibroma, café au lait spot, Lisch nodule, optic glioma, distinctive bony lesion (dysplasia of the sphenoid bone or long bone cortex) and freckle in the groin or axilla with no family history of neurofibromatosis. Brain magnetic resonance imaging (MRI) revealed about 6.7 cm diameter, a well defined highly enhancing mass in the right frontal lobe (). The preoperative differential diagnoses were glioblastoma multiforme, anaplastic astrocytoma, and malignant meningioma. A surgical resection was carried out through right frontal craniotomy.\nMacroscopically, it was a well-circumscribed yellowish nodular round mass having gelatinous surface without dural attachment (). It was intra-parenchymal tumor and had a distinct cleavage plane in the superficial brain parenchyma, but not in the deeper portion. Microscopically, the tumor was highly cellular and mainly consisted of spindle cells in interlacing and interwoven fascicles. Perivascular whirling and condensation of tumor cells were observed. The tumor was well-demarcated from the adjacent brain tissues. Each tumor cell had a fusiform nucleus and aligned in a convoluted form with a moderate degree of mitotic activity and a high nuclear-to-cytoplasmic ratio. Myxoid parts were scattered in the tumor ().\nImmunohistochemistry showed that the tumor cell was positive for S100 (), but negative for glial fibrillary acidic protein (GFAP), CD34, synaptophysin and desmin. These histological and immunohistochemical findings supported the diagnosis of a primary MINST.\nThirty times of fractionated whole-brain radiation were performed with 5760 cGy over the period of 6 weeks after surgery. Brain MRI follow-up examination was performed every six months, but there was no evidence of tumor recurrence. Brain MRI at 50 months after his first surgery revealed a 1.0×1.0 cm of well-defined enhancing mass in the right frontal convexity and leptomeningeal enhancement in the right frontal area (). Whole spinal MRI showed no evidence of metastasis. No malignant cell was observed in his cerebrospinal fluid study. Second gross total resection (GTR) was performed. The histopathological examination showed a primary MINST, which was consistent with the histopathological results from the first surgery. The brain MRI at four months after second surgery revealed a tumor of 1.0×0.5 cm in size in the right anterior frontal convexity and pachymeningeal enhancement in the right frontal area (). As the patient's guardian wanted to treat the patient in another hospital, so the patient was transferred to another hospital. Third GTR was carried out. The histopathological examination also showed a primary MINST. As the tumor was repeatedly relapsed despite the GTR which was performed twice before, radiation therapy and chemotherapy were performed according to the Korean Society for Pediatric Neuro-Oncology (KSPNO)-S081 Protocol, which can be used for a high-grade brain tumor. Thirty times of fractionated radiation were carried out with 6000 cGy after his third surgery and 4 times of combination chemotherapy with vincristine (1.5 mg/m2 IV push, Day 0, 7), etoposide (75 mg/m2 in normal saline dose ×2.5 times IV over 2 hours, Day 0-4), carboplatin (300 mg/m2 in normal saline 125 mL/m2 IV over 1 hour, Day 0, 1), and ifosfamide (1500 mg/m2 in dextrose water 200 mL/m2 with Mesna (300 mg/m2 IV over 1 hour, Day 0-4) were applied. The irregular enhancing lesion (3.0×4.0 cm) was found in a brain MRI at six months after the third surgery (). As the size of this lesion was found to be smaller than the previous one in the brain MRI at thirteen months after the third surgery, this lesion is considered to be the result of radiation injury rather than tumor recurrence (). He is still alive at 77 months after his first surgery and complaining of mild headache and dizziness, but there are no other neurological abnormalities.