From the Skin to Small Bowel: Metastatic Melanoma as a Hidden Source of Gastrointestinal Bleeding.

Malignant melanoma involving the small bowel, whether primary or metastatic, is rare and often remains undiagnosed during life due to its asymptomatic course or nonspecific clinical presentation. Here, we report the case of an 81-year-old man with a history of spindle cell melanoma of the scalp, treated five years earlier, who presented to the emergency department with loss of consciousness. Laboratory tests revealed severe anemia (hemoglobin: 4.2 g/dL), and rectal examination demonstrated melena. Upper and lower endoscopy failed to identify a bleeding source. Abdominal CT showed a circular filling defect in the proximal jejunum. Subsequent enteroscopy revealed an ulcerated, friable mass occupying more than 50% of the luminal circumference. The patient underwent laparoscopic segmental resection of a 10 cm jejunal segment containing the lesion, followed by primary anastomosis. Histopathological analysis confirmed metastatic malignant melanoma infiltrating the intestinal wall. Small bowel melanoma is a rare but important cause of gastrointestinal bleeding. In patients with a history of melanoma presenting with unexplained anemia or overt bleeding, small bowel metastasis should be considered. Surgical resection offers both diagnostic confirmation and effective treatment.