ABSTRACT
Ungual fibrokeratomas are sausage-shaped tumors arising from the depth of the nail pocket and lying on the nail, from the matrix and growing for a certain period in the nail plate, or from the nail bed and growing under the nail. Koenen's tumors of tuberous sclerosis are histologically alike fibrokeratomas. In principle, their treatment is the same as that of acquired fibrokeratomas; however, they are often multiple and can no longer be removed singly. There are many synonyms for this frequent degenerative lesion of the proximal nail fold of fingers and rarely toes, reflecting the different opinions as to its etiopathogenesis. Erythronychia describes a red nail, in most cases as a longitudinal red line under or in the nail, more rarely red spots or a red lunula. The biopsy techniques for multiple red lines and erythematous spots depend on their localization and size.
