A case of primary amelanotic malignant melanoma of the esophagus with multiorgan metastasis

Abstract

A 60-year-old man suffered from persistent vomiting and was admitted to our hospital. Esophagogastroduodenoscopy showed type 3 lesions affecting 2/3 of the circumference of the esophagogastric junction and submucosal tumor-like elevated lesions with erosions in the upper part of the stomach. Flat submucosal tumor-like elevated lesions were found in the duodenum. PET-CT showed FDG accumulation throughout the body. The biopsy from all lesions demonstrated that melanin pigment was negative and HMB45 and Melan-A were positive. Thus, he was diagnosed with an amelanotic malignant melanoma. No primary lesion was noted on the skin. Endoscopically, the lesions in the esophagogastric junction showed features consistent with those of primary malignant melanoma in the gastrointestinal tract, and the lesions in the stomach and duodenum showed features consistent with those of metastatic tumor in the gastrointestinal tract. Melanocytes were noted in the squamous epithelial tissue of the esophagus. Thus, this is a rare case of amelanotic malignant melanoma derived from the melanocytes of the esophagogastric junction, which grew and progressed in the stomach, resulting in multiorgan metastasis.