Juvenile pilocytic astrocytoma of the cerebrum in adults. A distinctive neoplasm with favorable prognosis.

Seven adults (15 years of age or older) with juvenile pilocytic astrocytoma of the cerebrum were treated at Barnes Hospital in St. Louis, Missouri, from 1950 to 1981. This group comprised 7% of the total adult population with well differentiated astrocytoma and astrocytoma with anaplastic foci treated over a 30-year period. All seven patients were less than 30 years old at the time of presentation. The tumors were characterized by distinctive histology, a predilection for the temporal lobe, the presence of a major cyst, and relative gross circumscription making total surgical resection feasible. In contrast to patients with diffusely infiltrating cerebral astrocytoma, those with juvenile pilocytic astrocytoma have had an extremely favorable course, regardless of treatment. Four were treated with surgery alone after total gross tumor excision, and three received postoperative irradiation after subtotal excision. Six were alive 27, 24, 17, 9, 5, and 2 years after initial surgery. One patient died 7 years after surgery and radiation as a result of cerebral radiation necrosis. Juvenile pilocytic astrocytoma of the cerebrum is a recognizable, distinctive entity with natural history and pathological characteristics similar to the relatively benign cerebellar astrocytoma of childhood.