Primary pulmonary hemangiopericytoma: early local recurrence after perioperative rupture of the giant tumor mass (two cases).

We report two recent observations of giant hemangiopericytoma of the lung, one in a 4-year-old child and another in a 65-year-old man. There were no specific clinical signs, but the radiologic appearance was rather characteristic in both cases, as were the histologic findings. Pneumonectomy was carried out, complicated in each case by rupture of the fragile, incomplete pseudocapsule and diffuse dissemination of necrotic tumor tissue in the operative field and opposite bronchial tree. Outcome was fatal in both cases within a few months, with extensive, rapidly growing metastases in the subcutaneous scar tissue of the thoracotomy and in the other lung and in one case with diffuse diaphragmatic and intraabdominal metastases. These two observations will offer some guidelines for better understanding of this rare localization of hemangiopericytoma, its natural history, and its optimal treatment, with special reference to the malignant potential and local recurrence rate.