A Case of Leiomyoblastoma Originated in the Duodenum

Most leiomyoblastomas originate in the stomach, and rarely in the duodenum. A case of leiomyoblastoma originated in the second portion of the duodenum of a 72-year-old woman is presented. 22 cases of the duodenal leiomyoblastomas have been reported in Japan. 4 cases of them showed malignant behavior and only one proved fatal. In our case, pancreatoduodenectomy was performed. No invasion and no metastasis of the lymph node were found on the macroscopic and the histologic examination. However, she was died with multiple metastasis of the liver and the retention of ascites 4 years later since the first surgery. The term “leiomyoblastoma”is commonly used for the epithelioid smooth muscle tumor. There are some cases in which it is to difficult to distinguish leiomyoblastoma from the neurogenic tumor in the ususal microscopic examinaton using hematoxylin and eosin staining. Immunohistological examination is indispensable for the differential diagnosis in our case. It must be proved that the tumor was smooth muscle origin on the diagnosis of leiomyoblastoma by the measns of various method, electron-microscopic or immunohistological examination, even though it showed typical findings on the usual microscopic examination.