Medulloblastomas in late middle age and the elderly: report of 2 cases.

Medulloblastomas may be difficult to recognize in late middle age and the elderly because of their rarity and their histological similarity, particularly in frozen sections, to common, poorly differentiated, metastatic tumors, notably the small cell carcinoma of lung. This report describes the occurrence of medulloblastomas in a 66-year-old male (case 1) and a 65-year-old female (case 2). Both tumors appeared radiologically as cystic cerebellar masses of irregular shape and variable intensity on magnetic resonance imaging; in each case microscopic examination revealed a primitive neuroectodermal tumor with focal astrocytic differentiation and desmoplasia. Case 1 died 23 months after surgery; an autopsy revealed extensive dissemination of the tumor to the bone marrow, small collections of malignant cells in the spinal subarachnoid space, and no evidence of local recurrence. Case 2 is well 29 months after her operation. The possibility of a medulloblastoma should be considered when a solitary cerebellar lesion is discovered in a middle-aged or elderly patient without a demonstrable extraneural primary site.