[Pulmonary hemangiopericytoma. Apropos of a case].

A primary pulmonary location of a hemangiopericytoma, a tumor of vascular origin developing from pericytes, is very rarely observed, no more than 40 cases having been reported in the published literature. Diagnosis cannot be based on clinical symptomatology, often inexistent, or on radiological findings which are not very characteristic, but depends on results of pathological examination. Malignant potentiality, assessed by the pathologist mainly by the presence of necrotic zones in the tumor, is evidenced by local recurrence and by metastases. The course is unpredictable and the tendency is for local recurrences to occur. The only current effective treatment is by excision.