Pilomyxoid astrocytoma with high proliferation index

Pilomyxoid astrocytomas is an uncommon aggressive piloid neoplasm, closely related to pilocytic astrocytomas and typically presents in the very young but can occur in older children and rarely in adults. A 12-years-old male presented with focal seizures, headache and vomiting of 10 days duration. Computed tomogram showed a hypo- to hyperdense and peripherally enhancing, solid-cystic lesion in the left temporal lobe. Histopathological examination revealed a characteristic tumor composed of bipolar cells arranged in dyscohesive sheets, angiocentric pattern in a loose myxoid background, with brisk mitotic activity and foci of necrosis. No Rosenthal fibers or eosinophilic granular bodies were seen. The tumor cells showed strong GFAP and scattered p53 positivity, but were negative for EMA. Ki-67 positivity ranged from 30 to 40%, highest reported till date. The patient was treated with radiotherapy and concurrent temozolamide and the tumor recurred after two years.