Flat Warts (Verrucae Planae) Confined to the Pigment of a Tattoo: A Rare Tattoo-associated Complication

Tattoos are a form of decorative body art in which pigment dyes of different colors are inoculated into the skin. It is estimated that 15-25% of general population has one or more tattoos (1), and the reasons for the popularity of this procedure may include greater social acceptance, aesthetic appeal, or perhaps the option of using laser removal techniques to eliminate unwanted tattoos. Even though modern professional tattoos are usually performed in sterile conditions, complications still occur, and with increasing numbers of people getting tattoos, the incidence of tattoo-associated side-effects presenting to dermatologists, which may be as high as 2%, is likely to increase (2). Herein we present a case of a 43-year-old male patient with multiple HPV-associated flat warts (verrucae planae) confined to the black pigment of a tattoo done 15 years ago. A 43-year-old patient presented to our clinic due to eczema on the trunk. However, during skin examination, we observed asymptomatic verrucous papules confined to the black ink of a tattoo done 15 years ago on the lateral side of his right lower leg (Figure 1a). Clinical examination showed multiple, discrete, skin-colored, verrucous papules disseminated exclusively within the lines of the black-colored tattoo. Full skin examination did not reveal any similar lesions anywhere else on the body. Dermoscopically, papules showed a discretely papillomatous surface and sharp borders (Figure 1b). The patient had another black tattoo on his trunk, in which no similar lesions were found. All his tattoos had been done more than 15 years ago in a professional tattoo salon and with no previous history of cutaneous lesions within tattoos. The patient had no other medical conditions and was not taking any medications. Additionally, no history of warts or other HPV-related lesions of the skin or mucosal membranes could be established. A biopsy of an individual papule was taken and sent for a histopathological analysis, which subsequently showed hyperkeratotic, orthokeratotic, and parakeratotic acanthotic epidermis with hypergranulosis and rare cells with perinuclear halo indicative of koilocytes (Figure 3b). Immunohistochemical analysis showed negative reaction for p16 and p53, while Ki67 was positive only in rare basal and suprabasal cells. These findings were indicative of low-risk HPV, and the diagnosis of HPV-induced verruca plana was ultimately established. The patient was then successfully treated with cautious curetta