A Report of a Keratoacanthoma-Type Cutaneous Squamous Cell Carcinoma Arising Within a Multicolored Ink Tattoo.

Keratoacanthoma (KA) is a common, low-grade, rapidly growing cutaneous squamous cell carcinoma that presents as an enlarging crateriform nodule, which may spontaneously involute but rarely metastasizes. Immunosuppression, ultraviolet light, viral infection, surgical procedures, and trauma are associated with their development. Overall, tattoo-induced squamous cell neoplasms are infrequently described in the literature. Carcinogenesis is hypothesized to result from trauma caused by the tattooing procedure or a foreign body reaction to the pigment. However, the pathogenesis has not been clearly defined. While most commonly associated with red ink, to date, very few cases of KA forming within black, blue, or multicolored ink tattoos are reported. Herein, we describe a case of KA arising within areas of blue and black pigment in a decorative ink tattoo.