Pineocytomas of childhood. A reappraisal of natural history and response to therapy.

Pineocytomas are pineal parenchymal tumors composed of differentiated cells histologically similar to those of the mature pineal gland. Little is known about the incidence, pattern of growth, or response to treatment of pineocytomas. Between 1975 and 1985, six children with pineocytomas were treated at our institution, and pineocytomas constituted 11% of all newly diagnosed pineal region tumors. The clinical, radiographic, and pathologic features of these six patients with pineocytomas are presented. Initial treatment for these children included craniospinal plus supplemental local radiotherapy (three), local radiotherapy alone (one), or radiation therapy plus adjuvant chemotherapy (two). Four of six patients had tumor recurrence a median of two years after diagnosis. Three patients had leptomeningeal dissemination, one at the time of diagnosis and two following therapy. Our findings suggest that: biopsy is necessary to distinguish pineocytomas from other pineal region tumors; radiation therapy alone is inadequate; and these tumors are aggressive in the pediatric population, with a high propensity for leptomeningeal dissemination.