SLOW GROWING FLAT‐TYPE PRIMARY MALIGNANT MELANOMA OF THE ESOPHAGUS TREATED WITH CAP‐ASSISTED EMR

We report a rare case of flat‐type primary malignant melanoma of the esophagus treated with endoscopic mucosal resection (EMR). A 64‐year‐old woman was referred for examination of a small pigmented lesion located in the mid esophagus. On endoscopy, the lesion exhibited almost no change in size over the year. Cap‐assisted EMR was performed en bloc. The histopathological findings showed atypical melanocyte proliferation in the basal layer, spindle cells, and epithelioid cell proliferation with nuclear enlargement and a few mitotic figures. Histopathological examination confirmed the diagnosis of primary malignant melanoma. Immunostaining for S‐100 protein and HMB‐45 antibody were positive, and the Ki‐67 index was low. The patient was discharged without additional surgical resection and/or chemotherapy. The patient had no symptoms and no signs of recurrence 20 months after EMR. There has been no report on a slow growing esophageal melanoma. It is difficult to estimate the malignant behavior of this case.