3064 A Case of a Rectal Xanthoma: A Sessile Polyp in an Uncommon Place

Abstract

INTRODUCTION: Xanthomas are benign collections of lipid bearing histiocytes that form a localized mass. While they are usually found in the soft tissue, they may also be found in the gastrointestinal (GI) tract. Within the GI tract, they are most commonly located in the stomach, and rarely within the rectosigmoid colon. These polyps are found within the mucosa and while usually asymptomatic, can rarely cause obstructive symptoms or pain if large enough. This case presents a rare finding of a rectal xanthoma. CASE DESCRIPTION/METHODS: A 55-year-old woman without any significant PMH presented for an initial screening colonoscopy. Physical exam and basic laboratory evaluation were unremarkable. Colonoscopy showed pan-diverticulosis, internal hemorrhoids, and a rectal polyp. The polyp was 4 mm, sessile, and yellow-white in color. It was removed with cold biopsy forceps. Pathology identified the polyp as a xanthoma. Given the benign nature of the polyp, patient was instructed to undergo screening colonoscopy in 10 years. DISCUSSION: During endoscopy, xanthomas are often overlooked as a differential diagnosis for a polypoid lesion, especially when found in an unlikely location. The exact incidence of rectal xanthomas is unknown and mostly limited to case reports alone. They can be seen in any age group, but tend to be more frequent with age. Colorectal xanthomas can present as flat, sessile, or pedunculated lesions. They are usually solitary and yellow-white in color. Xanthomas are typically confined to the lamina propria mucosa with pathology showing the characteristic foamy histiocytes in this location. Unlike cutaneous and tendinous xanthomas that often have a relation to hyperlipidemia, gastrointestinal xanthomas are usually not associated with an underlying disease (though this remains under investigation). The etiology of gastrointestinal xanthomas are poorly understood but it is believed that they arise in areas of damage, especially when they are found in the stomach. As xanthomas are benign and typically do not cause symptoms, there is no treatment necessary. Xanthomas continue to remain an important and rare finding within the GI tract that may eventually be found to have associations with certain systemic conditions.