[An autopsy case of well differentiated leiomyosarcoma of the jejunum]

A 54-year-old man had a leiomyosarcoma of the jejunum, 8 X 6 X 5 cm in size resected, on December 17, 1982 and died of liver metastases with hemorrhagic ascites (4,000 ml) on July 5, 1984. The malignant potential of a smooth muscle tumor based on the mitotic index of tumor cells has been stressed for many years. However, our biologically malignant autopsy case showed not only an exceptionally low mitotic index in tumor cells of the surgical specimen but also in those of the autopsy specimen. In this report, the fact that the degree of mitotic figures sometimes fail to indicate biological behavior is discussed.