Congenital hemangiopericytoma/infantile myofibromatosis: radical surgery versus a conservative "wait and see" approach.

Infantile/congenital hemangiopericytoma, although sharing many similar histological features with adult hemangiopericytoma, has a much better prognosis. Nevertheless, most cases described in the literature were pursued by radical surgery with or without adjuvant chemotherapy. We describe a neonate who presented with a huge mass in the right gluteus, 6 x 5 x 4 cm, and a small ventral abdominal mass. The masses were confirmed on biopsy according to light microscopy, immunohistochemistry, and electron microscopy as congenital hemangiopericytoma. They shrank spontaneously within 2 weeks and vanished within 2 months. We present a hypothesis that masses appearing in the neonatal period with this histology and with no life-endangering pressure on vital organs should routinely be dealt with conservatively.