S4567 A Surprise During a Screening Colonoscopy: Extensive Colonic Xanthomatosis Associated With Hyperlipidemia

Introduction: Gastrointestinal (GI) xanthomas are uncommon, benign lesions of the GI mucosa, often identified during endoscopy as yellowish nodules or plaques in asymptomatic patients. Their etiology is not fully understood but is thought to involve lipid-laden macrophages—foam cells—accumulating in the lamina propria, potentially associated with alterations in lipid metabolism and inflammation. GI xanthomas are typically observed as scattered lesions, while a diffuse, coalescing distribution is rare, with only a few cases reported in the literature. These lesions are most frequently found in the upper GI tract, with a reported prevalence of 0.23% to 7%. Colonic xanthomas are less common and less well documented. Case Description/Methods: A 50-year-old man with a history of hypertriglyceridemia and coronary artery disease, status post percutaneous coronary intervention, presented to the GI clinic for a screening colonoscopy. Recent laboratory results revealed normal total cholesterol and low-density lipoprotein levels, but an abnormally low high-density lipoprotein (<3 mg/dL) and elevated triglycerides (206 mg/dL). Colonoscopy revealed abnormal colonic mucosa with notable opacity, absence of typical vascular and glandular patterns, and an edema-like appearance. Segmental biopsies demonstrated mild chronic inflammation, focal hyperplastic epithelial changes, and foamy macrophages, confirming the diagnosis of extensive colonic xanthomatosis. During follow-up, the patient was informed of the diagnosis and counseled on dyslipidemia management to reduce future risk. Discussion: While several factors suggest a possible association between colonic xanthomas and cardiovascular disease, this relationship remains unclear. Similar lipid-laden lesions—such as xanthelasma and other extracolonic xanthomas—have shown associations with dyslipidemia and increased cardiovascular risk. Although the clinical significance of colonic xanthomas remains uncertain. This case highlights the value of screening colonoscopies not only in identifying premalignant lesions but also in detecting benign findings that may be indicative of broader systemic conditions. Interestingly, the relationship between diffuse xanthomatous lesions and malignancy remains uncertain. A case report by Yang et al. described an early-stage esophageal cancer associated with diffuse esophageal xanthomas, suggesting a potential risk factor for cellular derangement and a possible predisposition to malignant transformation.