Primary malignant melanoma of the gastrointestinal tract is extremely rare. A 35-year-old man presented with complaints of abdominal pain and weight loss. Contrast enhanced computed tomography showed a large mass involving the duodenum and the superior mesenteric vessels. Upper gastrointestinal endoscopy demonstrated a large, friable mass along the duodenal wall and biopsy was suggestive of malignant melanoma. A detailed physical examination and whole body imaging (positron emission tomography and computed tomography) did not reveal any other lesion.
The patient underwent a pancreaticoduodenectomy with segmental resection and anastomosis of the superior mesenteric vein as well as a segmental colectomy. His postoperative recovery was uneventful. The histopathology of the operative specimen showed a malignant amelanotic melanoma arising from the duodenum with lymph nodal involvement. He received oral temozolomide. However, he developed liver metastasis at six months and again at ten months, which was managed with radiofrequency ablation both times. He is doing well at 32 months of follow-up review. Multimodality treatment including surgery, adjuvant chemotherapy and salvage therapy appears to be a promising tool for achieving long-term survival in such patients.