Mass-Forming NSAID-Associated Colopathy Mimicking Right-Sided Colon Cancer: A Case Report.

Nonsteroidal anti-inflammatory drugs (NSAIDs) can cause mucosal injury throughout the gastrointestinal tract, yet NSAID-related colonic damage remains underrecognized. We report a rare case of an ulcerated colonic mass mimicking carcinoma in a patient with long-term NSAID exposure. The patient, a 63-year-old man with a history of coronary artery disease and coronary artery bypass grafting more than 25 years earlier, was receiving long-term dual antiplatelet therapy consisting of aspirin (81 mg daily) and clopidogrel (75 mg daily), as well as chronic pantoprazole therapy. He presented with a 4-day history of hematochezia without weight loss. Esophagogastroduodenoscopy revealed no bleeding source, but colonoscopy identified an ulcerated, nonobstructive mass in the cecum and proximal ascending colon. A biopsy revealed colonic mucosa with severe ulceration and granulation tissue. The subsequent right hemicolectomy specimen revealed a 5.5-cm, ill-defined ulcerative mass in the cecum and ascending colon. Microscopically, the cecum and ascending colon showed ulcerated mucosa with fibrosis, reactive changes, and foreign body material deposition, without evidence of malignancy. Immunohistochemical stains for cytomegalovirus (CMV) and herpes simplex virus (HSV) were negative. Following surgery, aspirin and clopidogrel were resumed because of the patient's cardiovascular risk. Approximately 1 year later, his hemoglobin level was 12.0 g/dL (6.7 g/dL before surgery), and no gastrointestinal bleeding, diarrhea, or abdominal pain was documented during that encounter. Because aspirin was continued, a clinical response to medication withdrawal could not be assessed. Based on the medication history, right-sided distribution, and histologic findings, the lesion was considered most consistent with suspected aspirin-associated colopathy presenting as a mass-like lesion. However, the concomitant clopidogrel and pantoprazole use and the absence of a formal aspirin dechallenge limited definitive causal attribution.