The Köenen’s tumor is a benign and painless lesion which has its origin in the nail matrix. This tumor appears in the eponychium with an elongated and ovoid shape and a cornified free extremity and it takes up a space of the proximal side of the nail. It has a pink or brownish-gray color.
The Köenen’s tumor is accompanied by an alteration of the whole part of the unguinal layer with a kind of sulcus or longitudinal canal shape.
Sometimes, the visualization of this pathology shows only the presence of such unguinal sulcus without the visibility of such tumor.
The Köenen’s tumors are one of the most frequent clinical signs of the tuberous sclerosis located in 50 % of cases.
The reason of the appearance of the Köenen’s tumor is still unknown, although the mutation of the TSC1 and TSC2 genes is closely related to the growth of the tumor.
The treatment for the Köenen’s tumor is surgical, being different the surgical applied technique, according to the location of the Köenen’s tumor and the affection of the unguinal layer. In this surgery it is extremely important the complete resection of the tumor until the origin of its implantation, requiring surgery at the level of the nail matrix.