An Unusual Case of Upper Digestive Bleeding-Metastatic Amelanotic Melanoma: Case Report and Literature Review.

Metastatic melanoma is one of the most common malignancies associated with the spread of the primary tumor. The primary site is usually the skin or the eyes. The most frequent site of metastases is the gastrointestinal tract, accounting for 60% of cases at autopsy. In 2% of patients, metastases occur without a detectable primary tumor. We present a rare case of upper digestive bleeding caused by multiple gastrointestinal tract metastases from an amelanotic melanoma. This case report describes a 65-year-old male who arrived at the emergency department after experiencing an episode of upper gastrointestinal bleeding (melena). One week prior to admission, he had been treated with nonsteroidal anti-inflammatory drugs for lower back pain due to L4-L5 disc herniation. Upper digestive endoscopy revealed multiple polypoid masses in the stomach and duodenum, and capsule endoscopy showed additional lesions in the small bowel. Histopathological examination confirmed the diagnosis: metastases from an amelanotic malignant melanoma. Abdominal and cranial computed tomography scans revealed multiple secondary lesions in the brain, gallbladder, retroperitoneal area, gastrointestinal tract, and peritoneum. Localized radiotherapy was applied to the cerebral metastasis, and systemic chemotherapy with dacarbazine was initiated, resulting in a partial clinical response. Unfortunately, the disease progressed, and the patient died one month after diagnosis. Metastatic melanoma of the gastrointestinal tract is an exceedingly rare cause of upper digestive bleeding.