Giant cell fibroblastoma. A distinctive, recurrent tumor of childhood.

Giant cell fibroblastoma, which was first described by Shmookler and Enzinger in 1983, is a rare fibroblastic tumor occurring mainly in male patients younger than 10 years of age. Only 28 cases have been reported so far. This paper describes seven new cases which were referred in consultation between 1968 and 1985. Five of the seven patients were male; their ages at the time of first surgery ranged from 2 to 18 years, but six of the seven were younger than 4 years. Tumors were all superficial and were situated in the chest (2 tumors), neck, axilla, scrotum, thigh, and finger; they generally grew slowly, were poorly circumscribed, and measured from 1 to 5 cm in maximum dimensions. Grossly, they were described variously as gray, gelatinous, firm, white, fibrous, pink, and watery. Histologically, there were varying proportions of moderately cellular solid areas and angiectoid areas, both featuring distinctive fibroblastic cells with what appeared to be multiple nuclei arranged in florets or wreaths. By electron microscopy, each wreath proved to be an excessively convoluted, but single, multilobed nucleus. The nuclei of the tumor cells were slightly hyperchromatic and not bizarre or pleomorphic. In follow-up times of from 12 months to 11 years (median 31 months), only one tumor recurred locally and none metastasized. The comparatively low recurrence rate in this series may well increase if the patients are followed for a longer period. Giant cell fibroblastoma should probably be classified with other nonmetastasizing, locally recurring fibroblastic proliferations of youth and childhood such as juvenile aponeurotic fibroma and recurring digital fibrous tumor of infancy.