Onychomatrixoma D21.1/21.2

Baran and Kint, 1992

Rare, benign (the dignity of the tumor is not conclusively clarified), only very slowly growing, fibroepithelial tumor of the nail matrix which leads to a painless, longitudinal proliferation, distension and yellow-brown discoloration and finally to a complete destruction of the nail matrix. Small splinter hemorrhages are often present in the proximal part of the nail.

Affected are 30-50 year olds.

Clinically, there is a painless, elongated-streaked discoloration and distension with thickening of the nail plate, the surface of which initially remains intact. On frontal view of the nail edge, a yellowish crumbly cystic-wabby (DD: onychomycosis) enforcement of the nail matrix becomes visible. This corresponds to the tumor.

Broad-based fibroepithelial growth that adapts to the nail contour. The polymorphic tumor stroma shows Cd34 positivity, further positivity for S100, actin and desmin. Furthermore described are myxoid stroma formations.

Subungual verrucous carcinoma; dorsal cyst; digital fibrokeratome.

Excision in a healthy person; the tumour tends to recur, so that careful attention must be paid to a careful excision in a healthy person.

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