Hemangiopericytoma in pediatric ages: a report from the Italian and German Soft Tissue Sarcoma Cooperative Group.

BACKGROUND: Hemangiopericytoma (HPC) is very uncommon in childhood and comprises two different clinical entities, the adult type and the infantile type, occurring in the first year of age. We report on a series of 27 pediatric patients treated from 1978 to 1999 by the Italian and German Soft Tissue Sarcoma Cooperative Group. METHODS: Seven patients had infantile HPC; complete resection was achieved in the tumors of five patients and chemotherapy was given to four patients. Twenty children had adult type HPC; nine received complete tumor resection (four patients at diagnosis and five at delayed surgery). Post-operative radiotherapy was administered to 15 patients, chemotherapy to 19. RESULTS: Six of seven patients with infantile HPC were alive in first remission; one patient died of disease. Chemotherapy achieved an objective response in four of four patients. Among the adult type HPC cases, 5-year event free survival was 64% (median follow-up 125 months); 12 patients were alive in first remission, eight patients relapsed and died of disease. Seven of 10 evaluable patients showed good response to chemotherapy. Statistically significant differences in outcome were observed in relation to Intergroup Rhabdomyosarcoma Study grouping, size, local invasiveness, and gender. CONCLUSIONS: Infantile HPC is a unique entity probably related to infantile myofibroblastic lesions and characterized by a high response to chemotherapy, which is required in case of unresectable, life-threatening tumors. In children over 1 year of age, HPC behaves like its adult counterpart; complete surgical resection remains the mainstay of treatment, but chemotherapy and radiotherapy seem effective and are recommended in all patients with incomplete tumor resection and/or locally invasive, large tumors.