Posterior Fossa Astroblastoma: A Case Report.

Astroblastoma is an extremely rare glial tumor that only rarely occurs in the posterior fossa. We report a case of posterior fossa astroblastoma in an adult patient to highlight its diagnostic challenges and management approach. A 38-year-old man presented with a two-week history of headaches and dizziness without focal neurological deficits. Cranial computed tomography (CT) and magnetic resonance imaging (MRI) revealed a well-defined 3.2 cm midline cerebellar mass containing both cystic and solid components, with a "cauliflower-like" enhancing solid portion and mild surrounding edema. The patient underwent a suboccipital craniotomy with complete microsurgical resection of the tumor, and he recovered well with no neurological deficits. Histopathology confirmed astroblastoma, showing characteristic perivascular pseudorosettes and hyalinized blood vessels. Tumor cells were immunopositive for glial fibrillary acidic protein (GFAP), epithelial membrane antigen (EMA) in a dot-like pattern, and D2-40. No high-grade features (such as increased mitotic activity, microvascular proliferation, or significant nuclear atypia) were observed, consistent with a low-grade tumor. No adjuvant therapy was administered, and at three-year follow-up, the patient remains recurrence-free. Astroblastoma in the posterior fossa is exceptionally uncommon, posing a diagnostic challenge due to its nonspecific clinical and radiologic presentation. This case underscores that definitive diagnosis requires histopathological confirmation and that complete surgical resection can achieve favorable long-term outcomes. Long-term surveillance is recommended given the potential for late recurrence.