Giant cystic leiomyoma of the sigmoid colon.

Smooth muscle neoplasms may occur anywhere in the gastrointestinal tract, but are rare in hindgut derivatives. We report a case of colonic leiomyoma which had undergone cystic degeneration and presented as a huge abdominal mass. The diagnosis was aided preoperatively by C.T. scanning and the cyst shown subsequently to contain 13 litres of fluid. We believe this could be the largest reported cyst of this type.