Retrospective multi-institutional study on hemangiopericytoma in Polish children.

Background: Pediatric hemangiopericytoma (HPC) is an extremely rare vascular tumor with little data available on its clinical course and management.

Methods: Fourteen children with HPC registered in Polish Pediatric Rare Tumors and Polish Pediatric Soft-tissue Sarcomas Studies between 1992 and 2002 are reported.

Results: Seven patients (F/M: 5/2, age 2-10 months) had infantile HPC, four of whom had primary tumors affecting superficial tissues of the trunk and upper limbs. No child had initial nodal or organ metastases. Primary excision (PE) was performed only in three patients with superficial lesions. They received no supplemental treatment. The remaining four children responded well to chemotherapy (CHT), entering complete remission after CHT alone (n= 2) or after delayed resection (n= 2). No relapses occurred and all patients were alive 48-146 months after treatment. Seven patients (F/M: 2/5, age 3.2-16.5 years) had adult-type HPC, five of whom had tumors localized in superficial tissues of the lower limbs or head/neck. All patients presented with locally advanced disease. PE was performed in five children (complete in four); all patients were alive at follow up of 40-127 months. Three patients died of recurrence after incomplete PE despite supplemental chemo- and radiotherapy.

Conclusions: Complete surgical excision remains the mainstay of treatment for both HPC types. In unresectable adult-type HPC adjuvant chemo- and radiotherapy should be administered in macro- and microscopic tumor residues, but the prognosis is poor despite supplemental treatment. High chemo-responsiveness of infantile-type HPC produces a favorable outcome even in cases of unresectable, life-threatening tumors.