A keratoacanthoma developed within the red pigment of a recently placed forearm tattoo in a patient.

Researchers described a 61-year-old female patient who presented with a 6-week history of a rapidly growing, solitary crateriform nodule within the red pigment of her right forearm tattoo, which was placed 2 months prior to presentation. The lesion measured 8 mm and had a central hyperkeratotic plug. Subsequent surgical excision revealed histopathologic features consistent with keratoacanthoma, including an inflamed squamous lesion with crateriform growth and glassy features. Histopathologic examination also demonstrated deposits of red tattoo pigment within the tumor epithelium.

Previously published literature identified 42 cases of tattoo-associated keratoacanthomas and squamous cell carcinomas,75% of which arose within red tattoo pigment. This proportion reflected both tumor types and was derived from previously reported cases rather than a new analysis conducted as part of the current report.

The predisposition of these lesions to red pigment remains incompletely understood.  Degradation of red azo pigments may contribute to their development, although the underlying mechanism has not been established. The researchers identified surgical excision as the first-line treatment for solitary keratoacanthomas, according to lead study author Emma K. Jackson, of Imperial College Healthcare National Health Service Trust, and colleagues.

The report was limited to a single patient and did not include comparative data or longitudinal follow-up. The previously published cases included both keratoacanthomas and squamous cell carcinomas, limiting conclusions specific to keratoacanthoma. Neither the case report nor the cited literature established the incidence of these tumors among patients with tattoos or demonstrated a causal relationship with red pigment.

The study authors reported no conflicts of interest.

Source: Skin Health and Disease