Immunotherapy against esophageal primary amelanotic malignant melanoma relapse

Melanoma is a malignant tumor derived from melanocytes. Esophageal melanomas occur infrequently, especially primary amelanotic malignant melanoma of the esophagus (PAMME), which is extremely rare. Here, we report the case of a 74-year-old man with an esophageal amelanotic melanoma on the esophagogastric junction (EGJ) found on esophagogastroduodenoscopy. Radical surgery for the tumor at the EGJ was performed with total gastrectomy and D2 lymph node dissection. Diagnosis of PAMME was confirmed postoperatively by immunohistochemical staining. Four months after the surgery, abdominal computed tomography revealed multiple liver metastases. The patient received seven cycles of nivolumab monotherapy and two subsequent cycles of nivolumab and ipilimumab, and these metastases diminished. Recently, new therapeutic agents including immunotherapy have been developed for malignant melanoma and these agents have the potential of improving the prognosis of PAMME. Here, we present new insights into the diagnosis and therapeutic methods that can be used against primary esophageal melanoma.