Coexistence of inverted follicular keratosis and trichilemmoma
Aroni Kyriaki, Apostolaki Katerina, Davaris Panayotis
Pathology Department of Athens University
Six cases of a rare benign dermal tumor, localized on the face of middle aged men are described. The paraffin sections were stained with haematoxylin-eosin, PAS and PAS diastase and were examined on light microscope. A microscopically coexistence of inverted follicular keratosis (upper part of the lesion) and trichilemmoma (lower part of the lesion) is observed. Both neoplastic conditions stemed from the outer root sheath of the follicular infundibulum and, specifically, the inverted f´llicular keratosis stemed from the infundibulum and trichilemmoma from the lower part of the hair follicle. Such intermediate neoplasms might occur along a spectrum with trichilemmoma at one end and inverted f´llicular keratosis at the other. The present series described by us would appear to support that contention. Pathologists should differentiate these tumours from basal cell carcinoma and sweat gland tumours.
Key words: Inverted follicular keratosis, Trichilemmoma, Skin.
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