Localised pseudoepitheliomatous hyperplasia: unusual cutaneous reaction pattern to tattoo.

Dear Editors, Tattoing has been practiced for centuries in many cultures, and has become increasingly popular in Western countries since the 1970s, with a parallel increase in adverse reactions. It is well established that tattooes may be associated not only with different skin diseases, like transient acute inflammatory reactions at the site of needling, but also with serious medical complications such as allergic contact dermatitis, contact urticaria, photodermatitis and other dermatoses like psoriasis, Systemic Lupus Erythematosus (SLE), sarcoidosis, lichen planus or localisation of skin cancer in the area of the tattoo. The reason for this occurrence has not been fully elucidated, but a locus minoris resistentiae or the isomorphism of Koebner has been hypothesised. Herein, we describe a case of a 26-year-old woman who presented to our clinic for an itchy overgrowing reaction at the tattoo site on the posterior side of her right leg. The tattoo had been placed about 6months prior to spotting the lesion and contained purple, green and blue-black pigment. Cutaneous examination showed a verrucous plaque limited to the purple area of the tattoo, where the patient had applied different topical antibiotic and corticosteroid ointments, without any benefit (Figure 1). Cultural examinations of the lesion were done to exclude an infective pathogenesis and showed negative results. A diagnosis of tattoo granuloma was considered and a cutaneous biopsy was performed. Microscopically, it has: hyperkeratosis, parakeratosis and striking pseudoepitheliomatous hyperplasia (PEH) (Figure 2), with marked perivascular and periadnexial mononuclear inflammatory infiltrate in the dermis and superficial epidermis, composed primarily of lymphocytes and histiocytes (Figure 3A–C). Dermal blackish pigment was also noted (Figure 4A, B). All these findings were consistent with the diagnosis of PEH at the tattoo site. The patient was treated with monthly intralesional triamcinolone injections and she is currently in follow-up. Although inflammatory reactions to tattoos are uncommon, more and more cases are being documented as tattooing becomes increasingly popular in today’s society. Different cutaneous delayed reaction patterns have been described, usually secondary to red pigment injection – the most common are allergic and lichenoid reactions, but granulomatous, pseudolymphomatous and morpheiform reactions can also occur (1,2) The development of cutaneous cancer has been rarely described in the area of a tattoo, but it could be coincidental (3–5). Figure 1 Clinical picture of hyperplastic epidermal reaction localised only to the red pigmented area.