Histopathology of the saburral tongue.

Optical microscopical studies were carried out on biopsies from 22 patients affected by saburral tongue (ST). The histopathological pattern consisted of a papillomatous acanthosis covered with a very thick horny layer. Abundant colonies of banal germs were seen in the keratin. There was an alternation of suprapapillary orthokeratosis and interpapillary parakeratosis. Under the keratin layer all the keratinocytes were large and clear with a glycogen-filled cytoplasm. Two specimens, studied with a transmission electron microscope, only showed that the keratinocytes were filled with glycogen. The clear glycogen-filled epithelial cells are common either in normal lingual epithelium or in some pathological conditions. The microscopic field of ST is quite similar to that of the hairy black tongue; but these peculiar clinical aspects of the tongue do not evolve one through the other.