Presentation
Disequiliberium and headache.
Patient Data
Large mass located centrally within the posterior fossa. It is a high T2 signal and low T1 signal with patchy contrast enhancement.
No normal vermis can be identified and the mass is likely to arise from it, near completely effacing the fourth ventricle and abutting the left inferior cerebellar peduncle and dorsal aspect of the brainstem without convincing evidence of extension into the pons.
As a result of the mass effect on the 4th ventricle, significant obstructive hydrocephalus has developed, with transependymal edema noted particularly at the frontal and occipital horns.
Case Discussion
The mass was resected and microscopic evaluation revealed:
Fragments of soft tissue including a neoplasm. It is composed of an atypical proliferation of cellular fragments having round to ovoid hyperchromatic nuclei and scant to ill-defined cytoplasm. They are arranged closely packed, at times with a tendency to incomplete Hommer-Wright rosettes, as well as in focal areas. Their processes oriented toward vessels showing pseudo-rosettes. The neoplasm shows prominent apoptotic and mitotic figures. IHC stains are positive for NSE and negative for GFAP in tumor cells.
Diagnosis:
Medulloblastoma, cerebellar mid-line involvement.
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