Epithelioid leiomyosarcoma with widespread metastases. Originating from the prostate?

Introduction: Leiomyosarcomas account for 0.1-0.2% of all prostatic tumors, only. An unusual case of epithelioid leiomyosarcoma of the prostate arisin g in hyperplastic smooth muscle cells is described. Patient and Methods: A 56-year-old man presented with dyspnea on rest and dry cough for 1 month. O n rectal examination the prostate was enlarged but a tumorous mass could no t be detected. The tumor caused distant metastases to the brain and the che st wall and a large pericardial effusion. The patient died 6 days after adm ission. The categorization of the tumor was made using immunohistochemistry . Results: The hypothesis that the tumor is primarily localized in the pros tate was supported by the histological finding of focal transition of hyper plastic smooth muscle cells of the prostate into tumor cell formations. The tumor cells showed immunoreactivity for epithelial keratin and smooth musc le actin, but not for vimentin and desmin. Routine morphological methods we re contributory to the diagnosis of a leiomyosarcoma arising in hyperplasti c smooth muscle cells. Conclusions:The tumor described herein essentially e ncapsulates the problem of the differential diagnosis of epithelioid-appear ing malignant soft-tissue neoplasms. Besides the morphological and the immu nohistochemical appearance of these tumors, a more favorable clinical cours e allows the differentiation from epithelioid leiomyosarcoma presented in t his case report.