Abstract

Leiomyosarcomas are very rare in lung. To date, several cases have been reported in literature since first discription in 1907, by Davidsohn. Pulmonary leiomyosarcoma is classified into primary and secondary forms. Primary from is known to be arisen from smooth muscle in the bronchi or blood vessles. The original sites of secondary pulmonary leiomyosarcoma are usually retroperitoneal soft tissue, gastrointestinal track or genitourinary track, especially uterus. We experienced a case of pulmonary leiomyosarcoma which was found in lower lobe of right lung from 40 years old man. Grossly, the tumor was a round shaped well circumscribed mass with rubbery hard consistency at the right lower lobe, measuring 7.5 cm in maximum diameter. The cut surfaces of the mass are somewhat lobulated, and show whorling pattern with focal necrosis and hemorrhage. Microscopically, the tumor is highly cellular and composed of interlacing bundles of spindle cells, which show moderate pleomorphism with motoses over 12/10 high power field. Electronmicroscopic examination reveal many numbers of microfilamants is in the cytoplasms of the tumor cells, which run parallel with longitudinal axis of the nuclei. The a report of a case and review of literature was discussed briefly.