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| T1 pre-gad | T1 post-gad | T1 post-gad |
Diagnosis: Medullary glioblastoma multiforme
Astrocytomas of the brain stem are typically pediatric tumors, although they may occur in adults. The most common location is the pons, followed by the midbrain and medulla. Patients often present with cranial nerve findings. Brain stem astrocytomas may be either focal or diffuse, with the focal lesions tending to enhance more. This patient has a history of a leg hemangiopericytoma which was treated by amputation. It was initially thought that this lesion might be a metastasis, however, an angiogram was performed which showed no significant vascularity. Biopsy showed the lesion to be a GBM. In adults, metastases account for most intraaxial, infratentorial masses followed by hemangioblastoma and glioma. The lack of a cystic component doesn't rule out hemangioblastoma since 40% are solid. Although high grade astrocytomas usually show some amount of neovascularity, the avascular angiogram makes hemangioblastoma and metastatic hemangiopericytoma very unlikely since they are both highly vascular tumors. Although unusual in this location, abscess may be a consideration as well. Related Cases
