Abstract: The clinicopathological features of 34 cases of cutaneous mixed tumor are reported.The specimens of 15 cases were studied immunohistochemically with 11 kinds of antibodies in order to establish their classification and to elucidate their histogenesis.The results were as follows: (1) Mixed tumors of the skin were basically apocrine or eccrine in type,apocrine type of mixed tumor was much more common than the eccrine one.(2)The epithelial elements of these tumors could be classified as tubuloglandular,solid nests and stromal cells.The inner cell layers of tubuloglandular components had distinct epithelial features,expressing keratin,carcinoembryonic antigen (CEA) and epithelial membrane antigen (EMA).The outer cell layers had negative results for actin, desmin, CEA, and EMA, and had positive results for vimentin, S100 protein, cytokeratin (11 cases), neuron-specific enolase (8 cases), and glial fibrillary acidic protein (6 cases).The immunophenotypes of stromal cells and solid nests were similar to those of the outer cell layers.These date suggest that the stromal components may derive either from the outer cells of the tubuloglandular elements or pluripotent stem cells, but can not confirm their exclusive myoepithelial origin.

Key words: Sweat gland neoplasms, Pathology, clinical, Immunohistochemistry