Anaplastic Pilocytic Astrocytoma: The “fusion” of good and bad. -Case report-

Abstract

Pilocytic astrocytoma is considered by the WHO classification of the CNS tumors (2007) as a benign neoplasm (grade I), whereas the same taxonomy applies to anaplastic astrocytoma a high grade of malignancy (grade III). The occurrence of tumors combining both features of pilocytic and anaplastic astrocytomas has been already described previously in a few case reports.

Herein, we present the case of a three years old boy, who presented signs and symptoms consistent with obstructive hydrocephalus caused by an intracerebellar sited neoplasm. The latter demonstrated both solid and cystic areas and contrast enhancement in the performed magnetic resonance imaging (MRI). The microscopic evaluation of the excised specimens showed the typical biphasic pattern of pilocytic astrocytoma together with Rosenthal fibers, eosinophilic granular bodies (EGBs) and hyaline droplets but also anaplastic features such as hypercellularity, endothelial proliferation, high mitotic index and focal necrosis.

Due to the rarity of this neoplasm and the absence of definite diagnostic criteria and exact grading, there are no consistent therapeutic approach, which in turn allows no accurate prognosis and prediction to be made. Therefore, it is our belief that this combined tumor should be reviewed accordingly and included as a distinct entity in WHO classification of CNS tumors.