Infantile hemangiopericytoma: a rare cause of a soft tissue mass.

A case of infantile hemangiopericytoma in a neonate is presented. The clinicopathologic characteristics of this tumor are described. This tumor is often confused for other more aggressive malignant tumors and, thus, is likely under-reported and overtreated. These tumors exhibit features suggestive of malignancy such as increased mitotic activity, nuclear pleomorphism, and increased cellularity, yet are clinically unpredictable. A conservative surgical approach is advocated.