In a 40-year-old male with past medical history of diabetes and orange skin, what is the likely cause of melena?

In this scenario, the patient presents with orange skin, which is indicative of jaundice and suggests a possible underlying liver condition. Given the mention of diabetes and the skin color, hemochromatosis may be a likely diagnosis. Hemochromatosis is a genetic disorder that causes excessive iron accumulation in the body, and it can lead to liver cirrhosis, which might cause portal hypertension.

Bleeding esophageal varices are a common complication of portal hypertension, most often seen in the context of liver cirrhosis. These varices can rupture and lead to melena, a term that refers to black, tarry stools resulting from the digestion of blood in the gastrointestinal tract.

While peptic ulcer disease, gastric cancer, and diverticulosis can also cause gastrointestinal bleeding, the combination of the patient’s orange skin (suggestive of liver pathology) and history of diabetes points towards a condition that affects the liver, making bleeding esophageal varices secondary to hemochromatosis the most probable cause of melena in this case.