Primary pulmonary hemangiopericytoma.

Eighteen cases of primary pulmonary hemangiopericytoma are reported. These pulmonary sarcomas tend to occur in older individuals, frequently as asymptomatic, non-calcified solitary masses on chest radiographs. Morphologically, they have a histology similar to their soft tissue counterparts. No single clinical or histologic feature allowed prediction of biologic aggressiveness in these rare pulmonary sarcomas and the authors recommend that all hemangiopericytomas of lung be considered as potentially malignant.