Adenoid cystic carcinoma of the skin--an immunohistochemical and ultrastructural study.

Adenoid cystic carcinoma of the skin was studied. Histologically, tumor cells were arranged in a tubular and a cribriform pattern, mainly int he reticular dermis. Immunohistochemically, epithelial membrane antigen was reactive with the tumor cells, but S-100 protein, vimentin, and carcino-embryonic antigen were not. On electron microscopy, we confirmed the findings of previous reports; tumor cells were arranged to form luminal structures; most of them were pseudolumina containing fine mucin granules, basal laminae, and collagen fibers, but some were true lumina with numerous microvilli and junctional complexes. New findings of this study were bizarre-shaped, electron-dense, net-like structures within the true lumina which were considered to be a type of mucin.