Immunohistochemical study of lysozyme in various benign sweat apparatus tumors.

We investigated the existence of lysozyme in various sweat apparatus tumors by adopting the avidin-biotin-peroxidase complex method. Positive reactions for lysozyme were found in four cases of apocrine cystadenoma, hidradenoma papilliferum, and an apocrine sweat apparatus benign tumor resembling "apocrine spiradenoma", all of which derive from apocrine sweat apparatus. On the other hand, in ten cases of syringoma, eccrine hidrocystoma, clear cell hidradenoma, eccrine spiradenoma, and eccrine poroma, which derive from eccrine sweat apparatus, no positive stainings for lysozyme were obtained. In four out of five cases of mixed tumor of the skin, the apocrine type exhibited positive results. Two cases of syringocystadenoma papilliferum were negative for lysozyme. The investigation of lysozyme in various sweat apparatus tumors is useful in determining the direction of differentiation in these tumors.