Abstract
Leiomyoma of the transverse mesocolon is very rare ; we report here the second known case in the Japanese literature. A 55-year-old woman was admitted to our hospital because of an intra-abdominal mass found on medical work-up. A fist-sized, hard, unmovable mass was palpated in the left upper abdomen. Echography revealed a well-defined, heterogeneous mass, and contrast-enhanced CT showed an 80×70×45-mm smooth mass with no contrast uptake. The preoperative diagnosis was an abdominal mass of unknown origin, and laparoscopic surgery was performed. The mass had grown on the surface of the transverse mesocolon without invasion to the surrounding tissue. The resected specimen was a white solid tumor. Histopathologic and immunohistologic studies revealed that it was c-kit (-), CD34(-), and SMA(+). The definitive diagnosis was leiomyoma arising from the transverse mesocolon. It is difficult to discriminate a benign leiomyoma from a malignant tumor because histologic findings do not always correspond with the grade of malignancy. After the operation, the patient has been free from recurrence over the last 2 years.
