Oleogranuloma of rectum co-existing with primary malignant melanoma: Report of a rare occurrence

Abstract

Oleogranulomas are rare in rectum and usually present as pseudotumor as a result of foreign body reaction secondary to injection into wall of any oily substance, most commonly mineral oil for treatment of hemorrhoids or oil enemas for constipation. Their occurrence along with malignant melanomas which are also uncommon tumors in the rectum have not been reported in the literature so far. We report one such rare occurrence in a 55-year-old female who presented with alteration of bowel habits and passage of blood in the stool. Clinical and radiological examination suggested a tumor in the rectum. The biopsy report was suggestive of malignant melanoma. The patient underwent abdominoperineal resection. Gross examination of resected specimen revealed blackish ulceroproliferative growth in the lower part of the rectum. Histopathological examination revealed characteristic features of malignant melanoma along with oleogranulomas comprising of multinucleated foreign body giant cells and epithelioid cell granulomas surrounding large clear spaces giving “swiss cheese appearance.”