Light and electron microscopic findings in a case of multiple lipid islands of the sigmoid mucosa are described. The patient apparently represents the second case with these lesions published in the medical literature. Lipid droplets were found in histiocytes, pericytes, smooth muscle cells, and Schwann cells. Pathological alterations of the nervous system in lipid islands have not been described before. The accumulation of lipids in different cell types of the colonic mucosa and the alterations of nervous elements are probably due to toxic factors reaching the cells either from the intestinal lumen or from the blood stream. The term "lipid proctitis (colitis)" does not appear to be useful because the lipid islands are obviously no disease sui generis but an epiphenomenon of other pathological processes. Pathological differential diagnosis and clinico-pathological correlation of colorectal lipid islands are briefly discussed.