Rectal Melanoma with Duodenal Metastasis: Very Unusual Endoscopic Findings
Melanoma of the GI tract is a rare and carries a poor prognosis. Most GI melanomas are metastatic from an oculo-cutaneous primary. Many hypothesize that melanoma of the GI tract is a product of spontaneous regression of an unknown primary. The etiology of primary GI melanomas is unclear. Hypothesis suggests it arises from the neural crest cells known to exist in the esophagus, stomach, small bowel, and ano-rectum.