A case of lipoma of colon that prolapsed from anus and caused invagination

Abstract

Lipoma of the large intestine has been said to be rare so far, but reported cases are increasing along with the common use of endoscopy. One resected case of a giant lipoma of the sigmoid colon that was found by invagination prolapsing through the anus is presented in this paper together with a review of literature. The patient was a man in his sixties who visited our hospital with a complaint of a tumor prolapsed through the anus. A yellowish, elastic soft tumor 8 cm in diameter with bleeding was noticed prolapsed. The tumor was manually reducible. A pedunculated lipoma of the sigmoid colon was diagnosed through various tests after admission to hospital. Since the complication of invagination was also found, Hutchinson's method and partial sigmoidectomy was performed with laparotomy. Histopathological findings revealed proliferation of adipocytes lobulated by fibrous tissues in the submucosa, and lipoma of the large intestine was diagnosed. Only 6 cases of lipoma of the large intestine that prolapsed from the anus including our case have been reported in Japan, and thus it is suggested that these cases are extremely rare.