Unusual manifestations of astroblastoma: a radiologic-pathologic analysis.

Astroblastoma is a very rare primary glial tumor occurring in children and young adults that is almost exclusively supratentorial in location. We report an extremely unusual presentation of a densely calcified posterior fossa astroblastoma with disseminated spinal and supratentorial metastasis. The mass exhibited neoplastic bone formation, which has not been reported, although calcifications are commonly seen in astroblastomas. A companion case of a low-grade astroblastoma that demonstrated classic histologic features but nonspecific and atypical imaging findings is also included. These cases expand the imaging and pathologic spectrum of this controversial tumor that shows highly variable biologic behavior and is difficult to distinguish from ependymoma.