Primary pulmonary leiomyosarcomas. A light and electron microscopic study.

Fewer than 100 cases of primary leiomyosarcoma of the lung have been reported, few of which have been studied by electron microscopy. We performed clinicopathologic studies, including fine structural analysis, of two such cases. Their ultrastructural features differed in part from those of other smooth-muscle tumors, which may help exclude other malignant pulmonary lesions from the differential diagnosis.