Background. The stomach is regarded as a rare site for metastasis. When a gastric mass is observed macroscopically, the presumed diagnosis is usually a primary gastric carcinoma. However, the stomach may be involved in metastatic malignant melanoma. Besides a possible macroscopical misdiagnosis, metastatic gastric melanoma may also be misdiagnosed microscopically as adenocarcinoma due to its protean histological characteristics. These features make metastatic gastric melanoma a challenging diagnosis in some cases.