Childhood hemangiopericytoma: review of St Jude Children's Research Hospital.

BACKGROUND: Hemangiopericytoma (HPC) is a heterogeneous, highly vascularized malignant soft-tissue neoplasm with 2 different clinical presentations: adult-type and infantile-type HPC. Intracranial HPC represents a special subtype with a high proclivity toward recurrence and metastasis.

METHODS: The authors have reviewed the clinical features, response to treatment, and outcomes of 17 patients with HPC treated at St Jude Children's Research Hospital from 1962 to 2009.

RESULTS: At diagnosis, 11 patients were older than 1 year (subgroup A) and 6 patients were younger than 1 year (subgroup B). Subgroup A: median age at diagnosis 13.5 years, (range, 4 to 20 y). Primary sites were intracranial (n=5), thigh (n=3), calf (n=1), foot (n=1), and scalp (n=1). One patient who presented with a thigh HPC had metastatic disease at diagnosis, and 3 patients with head location had unresectable tumors. Two patients with thigh location experienced objective responses to chemotherapy. Six patients died of disease progression, 4 of them had an intracranial location. The remaining 5 children are alive at follow-up of 12 to 32 years. Subgroup B: median age at diagnosis 0.5 months (range, 0 to 3 mo). Primary sites were thigh (n=2), calf (n=1), perianal (n=1), forearm (n=1), and lung (n=1). Three patients with limb location had unresectable disease at diagnosis, 2 of them experienced excellent responses to neoadjuvant chemotherapy and 1 did not show any response to chemotherapy and a staged resection was performed. All 6 infants are alive without evidence of disease at follow-up of 2 to 27 years.

CONCLUSIONS: Infantile HPC is characterized by a better clinical behavior than the adult type, which requires an aggressive multimodality therapy. Chemoresponsiveness and spontaneous regression have been reported in children younger than 1 year, suggesting that a more conservative surgical approach should be used. Intracranial HPC is considered as an aggressive tumor because of its propensity for recurrence and metastasis.