Clinicopathologic analysis and subclassification of benign lipomatous lesions of the colon.

Benign lipomatous lesions of the colon are generally asymptomatic. A few histologic subtypes are appreciable, but this is poorly studied. We categorized 404 benign colonic lipomatous lesions as vascular lipoma, fibrolipoma, mucosal lipoma, or lipoma not otherwise specified (NOS). We compared patient age and sex, tumor site and size, symptoms, whether the lesion was flat or pedunculated, and whether an overlying epithelial lesion was present. Symptomatic cases (4%) were larger on average than non-symptomatic ones (mean 3.70 cm vs. 1.30 cm, P < 0.0001). Lipoma NOS was commonly right-sided (P < 0.001) and commonly had an associated epithelial proliferation (P = 0.0004). Vascular lipomas were larger (mean 1.93 cm, P < 0.0001) than other types; they were the most commonly symptomatic, though this was not statistically significant. Mucosal lipomas were smallest on average (mean 0.48 cm) and were not associated with any clinical syndromes. Some colonic lipomas are non-incidental. Vascular lipomas are more often large, while lipomas NOS more often have an associated epithelial proliferation. Colonic lipomas are generally sporadic.