Atypical localization of metastatic melanoma in the gastrointestinal tract

Although most melanomas are diagnosed in early stages of the disease, a significant percentage show metastases from the beginning or during follow-up. The most common route is lymphatic, while hematogenous spread is less frequent. The most common site for metastases is the skin itself, although they can also occur in other organs, including the digestive tract, where the small intestine is the most frequently affected organ. We present the case of a 48-year-old woman with a history of superficial spreading melanoma of the cervical region, surgically treated 7 years prior and in remission, who presented with painless jaundice of 48 hours duration, without fever or other infectious focus. Upon arrival at the Emergency Department, she had a direct bilirubin of 7.9 mg/dL and a CRP of 140 mg/L. An abdominal ultrasound was performed, revealing biliary tract dilation without apparent cause, with secondary, apparently tumoral involvement of the gallbladder. During hospitalization, the study was completed with an abdominal CT scan, visualizing hyperdense lesions with a polypoid appearance in the gallbladder, in addition to the aforementioned intra- and extrahepatic biliary tract dilation. The cause was then identified as a hyperdense mass in the duodenum affecting the papilla, along with two other small hypervascular polypoid lesions in the second portion of the duodenum. With these findings, an ERCP was performed, revealing a papilla with a "pregnant" appearance, compatible with ampulloma, in addition to duodenal pseudopolyps of nonspecific appearance. The anatomopathological analysis was compatible with duodenal metastases from melanoma.