Duodenal and gallbladder metastasis of regressive melanoma: a case report and review of the literature.

Background: Malignant melanoma involving the gastrointestinal (GI) tract may be primary or metastatic. Small bowel is the commonest site of GI metastases from cutaneous malignant melanoma, metastatic lesion in the gallbladder is extremely rare.

Case Presentation: This case report describes the presentation of metastatic melanoma in duodenum and gallbladder. A 45-year-old man has presented melena with intermittent abdominal pain. On physical examination we found a small lesion between the fourth and fifth toes, associated with inguinal lymph node. An Abdominal ultrasound revealed diffuse duodenal thickening. Upper endoscopy was performed and discovered an ulcerative lesion in the second part of the duodenum. The biopsy with immunohistochemical stains was in favor of a duodenal location of melanoma. Computed tomography (CT) revealed many circumferential thickening of ileal loops associated with a nodular lesion in the anterior wall of the gallbladder. The patient was treated by palliative chemotherapy.

Discussion: Malignant melanoma of the GI tract may be primary or secondary. The small bowel is the most affected, but it's rare in the gallbladder. The clinical presentation can mimic the other intestinal tumors, and the diagnosis is based on imaging; CT scan and GI endoscopy have a key role on the diagnosis, and the treatment depends on the location and the number of lesions.

Conclusions: Metastases of melanoma in the GI tract are uncommon, the diagnosis must be suspected in any patient with a history of melanoma with digestive signs.