Massive pseudoepitheliomatous hyperplasia: an unusual reaction to a tattoo.

We document an unusual tattoo reaction presenting as verrucous plaques, which on histopathologic examination showed marked pseudoepitheliomatous epidermal hyperplasia. The patient is a 27-year-old female who presented to her dermatologist complaining of itchy overgrowth of her tattoo. Her symptoms began 2 months after tattoo placement approximately 1 year ago. Physical examination revealed verrucous plaques in the purple areas of the tattoo, suggesting a clinical diagnosis of a granulomatous tattoo reaction. A superficial biopsy showed epidermal hyperplasia somewhat reminiscent of a regressing keratoacanthoma. No tattoo was identified. A repeat shave biopsy demonstrated marked epidermal hyperplasia with focal keratin filled cystic dilatations, and local mild reactive keratinocytic atypia. In the surrounding dermis, there was dense chronic inflammation, fibrosis, and granules of dark red pigment. These findings suggest marked pseudoepitheliomatous hyperplasia secondary to the tattoo. Different reaction patterns have been described in association with tattoos, such as granulomatous and/or perivascular lymphocytic inflammation. However, there have been few cases reported of pseudoepitheliomatous hyperplasia arising at a tattoo site. Therefore, we encourage physicians to consider massive epidermal hyperplasia in the differential diagnosis of a verrucous tattoo reaction.