We report a case of a 38-year-old female patient with metastatic carcinoma of unknown origin. She had a one-year history of subcutaneous tumor in the left axillae, and visited Kitakyushu Municipal Medical Center Hospital. She underwent a resection of the tumor. Histopathalogically, a section showed an infiltration of round to polygonal tumor cells with eosinophilic granules in the abundant cytoplasm. The tumor cells did not demonstrate nests or glandular structure. Immunohistochemically, the tumor cells were positive for EMA, CAM5.2, S-100 protein, GCDFP-15, and negative for CEA and ER. We could not detect any primary tumors, and have therefore diagnosed this tumor as metatstatic carcinoma of unknown origin. [Skin Cancer (Japan) 2003; 18: 169-173]