METASTASIS FROM SKIN MELANOMA TO DUODENUM: CASE REPORTAND LITERATURE REVIEW

Tumor mass was observed after PET-CT scan in thedescending part of duodenum and pancreatic head by a 62-year-old Caucasian woman who had undergone skin melanoma resection from the anterior side of the right thigh (lower limb)associated with right inguinal lymphadenectomy 3 years earlier. Endoscopic examination with ultrasonography showed the tumor mass arising from the descending part of theduodenum, which had invaded the head of pancreas and caused loop obstruction. Endoscopic biopsy revealed neoplastic cells with melanin granules and positive cells for Melan-A/SOX10 staining, indicating the presence of a metastatic malignant melanoma. It showed no BRAF-Mutation. These additional stainings were evaluated after surgery. In the surgically resected Whipple specimen, the mass was 5 x 4 cm large, solid and ulcerated. Tumor infiltrated all duodenal layers and the tissue around them. Immunocytochemistry and electronic microscopy findings confirmed thediagnosis of metastatic malignant melanoma, and were similar to the skin specimen from the right thigh; therefore, the duodenal lesion was considered to be a metastasis from the right thigh.