Pseudomelanosis duodeni in a postrenal transplant patient.

Pseudomelanosis duodeni is a rare entity characterised by dark pigmented intracellular granules seen within macrophages that lie within the lamina propria of the duodenal villi. There is no known treatment, and the clinical significance and long-term sequelae of this entity are unclear. We present a case of pseudomelanosis duodeni in a 54-year-old woman who presented with a 1-month history of nausea, vomiting and non-bloody diarrhoea. The medical history was significant for diabetes mellitus type 2, end-stage renal disease status postkidney transplant, hypertension, anaemia of chronic disease and hypothyroidism. A gastroduodenal endoscopy revealed pigmented dark lesions in the duodenal mucosa. Biopsies from the second part of the duodenum and duodenal bulb showed pigmented macrophages in the lamina propria. The findings were consistent with duodenal melanosis. In spite of renal transplant with normalisation of renal function, the duodenal melanosis persists, which raises questions on the role of renal impairment in this entity.