Ultrastructural study of hereditary benign intraepithelial dyskeratosis.

Specimens taken from the buccal mucosa of two patients with hereditary benign intraepithelial dyskeratosis (HBID) were studied with the transmission electron microscope. Ultrastructural features were described and compared with those of white sponge nevus and Darier's disease. Ultrastructural findings in HBID revealed the presence of numerous vesicular bodies in immature dyskeratotic cells, densely packed tonofilaments filling the cytoplasm of mature dyskeratotic cells, and the disappearance of cellular interdigitations and desmosomes in mature dyskeratotic cells.