The paper describes a case of diffuse leiomyomatosis of the lung in a 45-year-old female. Leiomyomatosis, a disease noted in females, is considered to include 4 types of multiple smooth muscle lesions: 1) benign metastasizing leiomyoma; 2) lymphangioleiomyomatosis; 3) leiomyomatous peritoneal dissemination; and 4) intravenous leiomyomatosis. The authors present a classification proposed by E. Martin who attempts to pool in it all multiple leiomyomatous lesions observed in females, males, and children.