Rectosigmoid (colonic) xanthoma: a report of four cases and review of the literature.

AIM: Xanthomas of the colon appear to be rare lesions. Four cases are reported to bring wider attention to this entity.
METHOD: Slides, reports and clinical notes from all cases coded as colonic or rectal xanthoma or xanthelasma during the period 1 January 1993 to 1 January 2000 were reviewed. The clinicopathological features are described and integrated into a review of nine previously reported cases.
RESULTS: The ages of the patients ranged from 51 to 62 years (2M, 2F). Three lesions were located in the sigmoid colon and one in the rectum. They were all incidental findings at colonoscopy. Grossly, they varied from cream to yellow papules/polyps, ranged in size from 1 to 4mm and were all solitary. Two patients had an associated rectosigmoid hyperplastic polyp. There were no associated cutaneous xanthomatous lesions. One patient was diabetic and the serum lipid levels were normal in all patients. Histologically, all cases consisted of aggregates of mucosal foamy macrophages but in one case there were also macrophages involving the muscularis mucosae. The macrophages were negative for mucin and cytokeratin but were positive for CD68.
CONCLUSION: Colonic xanthomas do not appear to be the cause of lower gastrointestinal symptoms and are an incidental colonoscopic finding as well as at times being seen in association with colonic polyps.