IMMUNOHISTOCHEMICAL EVALUATION OF TENASCIN IN BENIGN ECCRINE GLAND TUMORS - COMPARISON WITH LAMININ AND FIBRONECTIN

Surgically resected specimens of skin appendage tumors, spiradenoma, p oroma of eccrine glands, syringoadenoma, syringoadenoma papilliferum a nd mixed tumor of skin were evaluated for tenascin, as well as the bas ement membrane-associated protein laminin, and the extracellular matri x protein fibronectin, using immunohistochemical methods. In normal sw eat glands, tenascin was localized as a delicate, thin band in the imm ediate vicinity of the basement membrane and laminin was limited to th e basement membrane. Tenascin in syringoadenoma was also expressed lin early adjacent to the basement membrane. Mixed tumors of skin showed a characteristic distribution of tenascin in the modified myoepithelial cell area adjacent to the tumor epithelia with a heterogeneous patter n, and particularly strong expression in the hyalinous and chondroid a reas. In addition, the localization of laminin in the basement membran es of tumors, intracellular immunoreactivity was observed in syringoad enoma, syringocystadenoma papilliferum, and mixed tumor of skin. Fibro nectin reactivity was visualized as a diffuse staining in the tumor st roma of eccrine poroma but its expression was restricted in eccrine sp iradenoma. The present study suggests a heterogeneity in the distribut ion of basement membrane and extracellular matrix proteins in skin app endage tumors and elucidation of their functional roles would assist i n understanding the changes in the supporting tumor stroma following n eoplastic changes.