Multiple Keratoacanthomas after a Recent Tattoo: A Case Repo
A 39-year-old Caucasian man presented to our outpatient department with seven painless, non-itchy papules within a recent tattoo. They appeared around 3 weeks after the patient had received a large tattoo covering the ventral aspect of the right thigh. Initially, the lesions grew rapidly, then their growth later stagnated. Physical examination revealed unilateral erythematous dome-shaped papules ranging from 4 mm to 1 cm in diameter. Five out of the seven lesions arose within the red-inked area and two within the black/gray-inked area. The papules were mostly capped with a thin crust. The patient has no past medical history and no further symptoms. He had had multiple tattoos in the past without complications. Recent sun exposure was denied.

An excisional biopsy revealed well-circumscribed symmetric tumors with a central keratin-filled crater. The cytologic atypia was mild and the tumors were accompanied by neutrophilic microabscesses and a mixed cell infiltrate. Therefore, the clinical and histopathological findings were consistent with multiple keratoacanthomas (KAs).

After DNA hybridization and PCR amplification using the VisionArray primer, human papillomavirus 6 (HPV6) (low-risk) was detected. The test was not reproducible in two further biopsies. All seven lesions were later excised with a minimal safety margin of 2 mm. A 3-month follow-up showed no further lesions.

Several dermatological complications have been reported as a result of tattooing. The incidence of tattoo-related skin neoplasms is rising. Here, authors reported a case of multiple KAs arising from both black/gray and red ink. Many etiologies for the formation of skin tumors in tattoos have been proposed, but it is difficult to prove a direct causality. Pigment toxicology to better understand tattoo safety should be researched more. Lastly, it is important to implement standardized regulations regarding the use of pigments in tattooing.