Primary malignant melanoma of the esophagus is extremely rare, with less than 200 cases reported in the literature. However, primary malignant melanoma is an aggressive tumor. We report a case of primary esophageal malignant melanoma that presented with a large polypoid mass in the lower esophagus, and subsequently showed multiple metastatic nodules in the subcutaneous layer, skin and retroperitoneum. Primary malignant melanoma should be included in the differential diagnosis of a polypoid esophageal mass, especially in cases where metastases to unexpected areas occur or in cases of unexpected metastatic patterns.