Introduction: Melena remains a common reason for inpatient admission and GI consultation. Here we present an unusual etiology for melena.
Case Description/Methods: 72 y/o M who presented with a month of dark stools and new finding of anemia on outpatient labwork. He has a history of melanoma, treated with wide local excision 8 years ago, and was recently diagnosed with recurrence of melanoma with lesions found in his brain and lungs. He denied any abdominal pain or prior history of GI bleeding. He took Xarelto for atrial fibrillation but denied use of NSAIDs or antiplatelet agents. His vitals on arrival were normal with exam unremarkable apart from facial and conjunctival pallor. His hemoglobin on arrival was 6.7 and he received three units of PRBCs during the course of his hospitalization.
He underwent both upper endoscopy and colonoscopy for evaluation of his anemia. EGD revealed too numerous to count black lesions scattered throughout the stomach and duodenum ranging from 0.2 cm to 1 cm in size. A few of the larger lesions had an ulcerated center with a clean grey base. During colonoscopy, he had similar black lesions throughout the left and ride side of his colon. Biopsy showed positive MART-1 staining supportive of metastatic melanoma throughout the digestive tract.
Discussion: Metastatic melanoma to the digestive tract is one of the most common metastatic malignancies to the digestive tract, occurring in about 60% of patients. While common, metastatic lesions in the digestive tract are typically not found until autopsy as many patients remain asymptomatic. Larger, polypoid metastatic lesions start to ulcerate once growth has exceeded its blood supply. Metastatic lesions tend to deposit in the submucosa causing surrounding wall thickening and a central ulceration characteristic for a “bulls-eye”. Melanoma metastases can present decades after the primary location is found making endoscopic evaluation paramount in patients with prior melanoma presenting with GI bleeding. Metastatic melanoma in the digestive tract is most commonly found in the small bowel, but can be found anywhere in the GI tract. The small bowel was not evaluated in our patient given the widespread metastases already seen with EGD and Colonoscopy. Patients with metastatic melanoma to the GI tract are treated with targeted immunotherapy or surgical resection for persistent anemia or obstruction. This case demonstrates the need to consider metastatic melanoma in the differential in a patient with GI symptoms and a history of prior melanoma.
Figure: Figure: Top Left, Retroflexed view of the stomach with ulcerated mucosa. Top Middle, Forward view of gastric body with metastatic deposits of melanoma, Top Right, Metastatic Melanoma in the Colon. Bottom Left, H&E stain from metastatic lesions. Bottom Right, MART1 stain confirming melanoma
Shashank Vemala indicated no relevant financial relationships.
Trupti Akella indicated no relevant financial relationships.
Steven Kaplan indicated no relevant financial relationships.
Shashank Vemala, MD, Trupti Akella, MD, Steven Kaplan, MD. P1567 - Melanomatous Melena, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.