Melanosis? Think Again: A Case of Pseudomelanosis duodeni and Jejunal Hemangiomas

Abstract

Melanosis coli is a common cause of hyperpigmented lesions in the GI tract that typically result from laxative overuse. Herein we describe a case of pseudomelanosis duodeni and jejunal hemangiomas discovered after push enteroscopy for an un-localized GI bleed. Though similar in appearance, pseudomelanosis is actually due to deposition of hemosiderin in lamina propria (LP) macrophages. An 83-year-old Asian female presented with recurrent hospitalizations for melena and severe anemia. Past medical history included transfusion-dependent iron deficiency anemia from chronic GI bleeding, hypertension, diabetes, heart failure, and atrial fibrillation not on anticoagulation. Her initial workup began in 2014 and EGD demonstrated erosive gastropathy with negative H. pylori. Colonoscopy demonstrated three 3-5 mm polyps and diverticulosis but no signs of acute bleeding. Repeat hospitalization for anemia with EGD in 2015 showed no source of bleeding. Colonoscopy showed two 5-8 mm polyps and diverticulosis but no bleeding. Outpatient capsule endoscopy in 2015 was unrevealing. Repeat hospitalization in April 2018 with colonoscopy revealed melena from the ileum and several small polyps in the cecal region. Push-enteroscopy revealed dark speckled pigmentation in the duodenum and jejunum. Two bleeding hemangiomas in the jejunum were found and ablated with APC then clipped. Duodenal biopsies demonstrated hemosiderin deposition within the LP macrophages consistent with a diagnosis of pseudomelanosis duodeni. Pseudomelanosis duodeni is characterized by the presence of brownish or blackish pigmentation in duodenal mucosa. It is associated with various medical conditions including, diabetes, renal disease, GI bleeding, hypertension, heart failure, oral iron intake, and use of erythropoiesis-stimulating agents. Histologic differential includes hemochromatosis, brown bowel syndrome, and malignant melanoma. Pseudomelanosis duodeni has histology notable for iron sulfide and hemosiderin deposits in the LP macrophages. This is in contrast to the accumulation of lipofuscin in the LP macrophages due to laxative overuse seen in melanosis coli. Interestingly, the hyperpigmentation made it easier to identify the jejunal hemangiomas; in a similar fashion to melanosis coli making it easier to identify polyps. Although this disease is quite rare and benign, it warrants tissue biopsy to rule out other worrisome etiologies.2546_A Figure 1. Dark speckled pigmentation scattered throughout the small bowel.2546_B Figure 2. Hemangiomas in the jejunum (blue/white arrows). Right image shows bleeding hemangioma (blue/white arrow).2546_C Figure 3. Left image demonstrates mucosal changes after APC ablation of bleeding hemangiomas (white/blue arrows). Right image demonstrates clips placed (red/white arrow) after APC ablation.