In adults, medulloblastoma represents only 1% of all malignant brain tumors. It typically affects younger adults (between 20 and 40 years of age). Only about adults are diagnosed with medulloblastoma each year in the United States. Doctors have identified three subtypes of adult medulloblastoma. Methods: Between and , 32 adult patients (age, > or =16 yr) with medulloblastomas confined to the craniospinal axis were treated in our institutions. Twenty cases involved classic histological features and 12 involved the desmoplastic variant.