Surgically resected specimens of skin appendage
tumors,
spiradenoma,
poroma of eccrine glands, syringoadenoma, syringoadenoma papilliferum and mixec
tumor of skin were evaluated for
tenascin, as well as the basement membrane-associated
protein laminin, and the
extracellular matrix protein fibronectin, using immunohistochemical methods. In normal sweat glands,
tenascin was localized as a delicate, thin band in the immediate vicinity of the basement membrane and
laminin was limited to the basement membrane.
Tenascin in syringoadenoma was also expressed linearly 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 pattern, and particularly strong expression in the hyalinous and chondroid areas. In addition, the localization of
laminin in the basement membranes of
tumors, intracellular immunoreactivity was observed in syringoadenoma,
syringocystadenoma papilliferum, and mixed
tumor of skin.
Fibronectin reactivity was visualized as a diffuse staining in the
tumor stroma of
eccrine poroma but its expression was restricted in
eccrine spiradenoma. The present study suggests a heterogeneity in the distribution of basement membrane and
extracellular matrix proteins in skin appendage
tumors and elucidation of their functional roles would assist in understanding the changes in the supporting
tumor stroma following neoplastic changes.