Lipomas occur through the intestinal tract, from the hypopharynx to the rectum, the colon having the highest incidence, where
lipomata are the commonest
benign neoplasm after adenomata. Nevertheless they are uncommon. CASE REPORT. 1) A 68-year-old man presented as an emergency with
abdominal pain associated with bowel obstruction. He had a 2 to 3 month history of intermittent right-sided
abdominal pain,
constipation spontaneously resolved. At
laparotomy there was a mass of the transverse colon, next hepatic flexure. A right
hemicolectomy was performed. The patient made an uneventful recovery. Histologic examination showed a
lipoma of the submucosal plane. 2) A 65-year-old man presented as an emergency with lower
abdominal pain associated with a prolapsed rectal
polyp. He had 1 month history of passing fresh blood per rectum. Ap ast colonoscopy revealed a large polypoid lesion in the descending colon. Transanal examination revealed a polypoid lesion with a maximum diameter of 4 cm, acting as an intussuseptum. Transanal polypectomy was performed. At
laparotomy there was an intussuseptum of the descending colon into the rectum: a left
hemicolectomy was performed. Histology showed the
polyp to be a submucosal
lipoma. DISCUSSION.
Lipomas are the most common benign nonepithelial
tumors of the colon.
Lipomata of the large bowel are reported as incidental findings in 0.3-0.5% of cases in large series of autopsies. In the wall of the intestine most lie in the submucosal plane, less frequently they are found in the subserosal plane. The commonest site for symptomatic solitary large bowel
lipoma is the ascending colon, including the caecum, followed by the transverse colon, including both hepatic and splenic flexure, descending colon, sigmoid colon and rectum. The peak incidence for
lipomata of the large bowel is in fifth-sixth decade. Colonic
lipomas are generally asymptomatic but occasionally patients may have intermittent crampy
abdominal pain secondary to
intussusception of a pedunculated
lipoma or with intermittent fresh rectal
bleeding. On barium enema
lipomas appear circular, ovoid, well demarcated, and smooth. A barium enema showing a relatively radiolucent mass, caused by the radiolucency of fat, is suggestive of a
lipoma. The water
enema, with water as the
contrast agent, accentuates the difference in density between a
lipoma and surrounding tissues. Another characteristic feature of
lipomas on barium enema is said to be their fluctuation in size and shape during the study: "squeeze sign".
Lipomas of the large bowel can be seen, however, by colonoscopy. On computerized tomography scan the
lipoma has a uniform appearance and density. In expert hands pedunculated and sessile lesions can be removed endoscopically, but often large bowel
lipomata are treated on the basis of a presumptive malignant diagnosis with exploratory
laparotomy. CONCLUSION. Colonic
lipomas, although unusual, continue to present difficulties in the preoperative differentiation between malignant and benign
colonic neoplasm. Two cases of colonic
lipomas are reported.