P0369 - An Unlikely Etiology of Colon Masses in a Patient With Three Known Primary Malignancies

Mindy Chen, MD¹, Tanima Jana, MD, FACG^2
1University of Texas at Houston, Houston, TX; ²University of Texas Health, McGovern Medical School, Houston, TX

Introduction: Renal cell carcinoma (RCC) is the most lethal urogenital cancer and constitutes 3% of all cancers. It is commonly found to be metastatic at the time of diagnosis, most often to the lymph nodes, lung, liver, and bone, but rarely to the gastrointestinal tract. Here we present the case of a patient with 3 known primary malignances who underwent endoscopic evaluation for iron deficiency anemia. Colonoscopy revealed multiple colon masses secondary to metastatic RCC.

Case Description/Methods: A 76-year-old man with a history of metastatic adenocarcinoma of the salivary glands (lung metastases, on maintenance pembrolizumab), RCC (diagnosed 5 years prior, treated with cryoablation, in remission), prostate adenocarcinoma (treated with radiation therapy, in remission), and hypertension presented with iron deficiency anemia felt to be out of proportion to his known active malignancy. Upper endoscopy was unrevealing. Small bowel capsule revealed nonbleeding small bowel erosions and ulcerations. Colonoscopy showed three distinct ulcerated, necrotic, and fungating masses in the proximal transverse colon (Image 1), distal transverse colon (Image 2) and descending colon (Image 3). Histology showed a poorly differentiated neoplasm composed of pleomorphic cells with abundant eosinophilic cytoplasm without gland formation. Immunochemical staining confirmed a diagnosis of metastatic RCC. The patient had progression of disease on lenvatinib and was transitioned to belzutifan. He ultimately underwent total colectomy due to persistent GI bleeding.

Discussion: While anemia is common in patients with RCC, it can be worsened due to gastrointestinal metastases. Our case is unique in that a patient with three separate non-GI malignancies was found to have multiple distinct malignant colon masses. Pathology of the masses showed metastasis from RCC, which is extremely rare. This highlights the importance of considering endoscopic evaluation in patients with iron deficiency anemia even if they have a known active non-GI malignancy.



Disclosures:


Mindy Chen, MD¹, Tanima Jana, MD, FACG². P0369 - An Unlikely Etiology of Colon Masses in a Patient With Three Known Primary Malignancies, ACG 2024 Annual Scientific Meeting Abstracts. Philadelphia, PA: American College of Gastroenterology.