Unusual occurrence of supratentorial medulloepithelioma in a young female

Abstract

Medulloepithelioma is an extremely rare PNET in late adolescence and adults with only two cases noted in literature. These are WHO grade IV tumors with dismal prognosis. Only few cases survived beyond 5 months. We report a rare case of supratentorial medulloepithelioma in a 17 year old girl. She had presented with right sided weakness, headache and vomiting. Imaging showed an enhancing mass lesion in left parietal region which undergone gross total resection. After surgery, her headache, vomiting and right sided weakness improved. On histopathology, the tumor had characteristic trabecular, ribbon and palisaded arrangement with brisk mitotic activity, necrosis and calcification. Immuno-histochemistry revealed positivity for Synaptophysin, Vimentin and EMA while GFAP was negative. MIB-1 labeling was very high. Patient received postoperative radiotherapy. On follow up after 14 months, she was clinically asymptomatic with no recurrence on imaging.

Keywords: Late adolescence and adults; medulloepithelioma; primitive neuroectodermal tumor; supratentorial.

Figure 1

(a and b) The axial T2W/FLAIR image shows a large extra-axial mass lesion with heterogenous signal intensity and edema of the adjacent brain parenchyma; (c and d) The axial T1W image shows a hypointense lesion, which shows strong heterogeneous enhancement; (e) DWI shows areas of restricted diffusion; (f) MRS shows elevated choline; (g) Postoperative T1W images reveal no residual mass lesions

Figure 2

The tumor shows immature neuroepithelial cells in papillary (a) and trabecular arrangement (b), with a PAS positive external limiting membrane (c), and necrosis and calcification (d). The tumor cells show strong synaptophysin (e) and focal EMA positivity (f), while GFAP is negative (g). MIB-1 labeling is high (h). [a and b: H and E, ×Obj.10, c: PAS ×Obj.20, d: H and E, ×Obj.20, e: Synaptophysin ×Obj.20, f: EMA ×Obj.40, g: GFAP ×Obj.10, h: MIB-1 ×40]