Hemangiopericytoma: characteristic features observed by magnetic resonance imaging and angiography

Hemangiopericytoma is a rare vascular tumor which may originate wherever there are capillaries. We report a case of this tumor occurring in a 79-year-old Japanese man, which originated from the subcutaneous tissues of the left upper arm and reached a size of 6 x 5 x 4 cm. Histopathological and electron microscopical findings were compatible with those of benign-type hemangiopericytoma. Magnetic resonance imaging showed the most intense signal on proton density images. Angiography showed the characteristic tumor feeder artery forming a pedicle which entered the tumor and branched radially and a dense, uniform, well-demarcated, oval tumor stain. These images were helpful in performing proper operative treatment without noteworthy bleeding. These modern modalities are excellent non-invasive treatment without diagnostic procedures for the vascular tumors of soft tissues in dermatology.