Objective:

To describe a keratoacanthoma arising within red tattoo pigment.

Approach:

• Case report: Researchers reported the clinical and histopathologic findings in a 61-year-old woman with a rapidly growing forearm lesion.
• Literature context: The report cited previously published cases of tattoo-associated keratoacanthomas and squamous cell carcinomas.

Key Findings:

• Two months after receiving a forearm tattoo, the patient presented with a solitary 8-mm crateriform nodule within its red pigment; it had grown over 6 weeks.
• Excision showed histopathologic features consistent with keratoacanthoma, with red tattoo pigment deposits in the tumor epithelium.
• Previously published literature identified 42 tattoo-associated cases of keratoacanthoma and squamous cell carcinoma; 75% arose within red pigment.

Interpretation:

The reason these lesions have been reported in red tattoo pigment is not established. Degradation of red azo pigments has been proposed as a possible contributor, but a mechanism has not been demonstrated.

Limitations:

• The report describes one patient and provides no comparative data or longitudinal follow-up.
• The cited cases included both keratoacanthomas and squamous cell carcinomas, limiting conclusions specific to keratoacanthoma.
• Neither the report nor the cited literature established tumor incidence among people with tattoos or a causal relationship with red pigment.

Conclusion:

The authors identified surgical excision as first-line treatment for solitary keratoacanthomas. The study authors reported no conflicts of interest.

Sources:

• Skin Health and Disease