A 63-year-old man is referred for diagnosis and treatment of lesions on both hands and wrists, which were first noted several weeks ago and have been increasing in number. According to the patient, all the lesions have remained asymptomatic. The patient’s history is positive for leukemia and, most recently, colon cancer. Physical examination of the lesions reveals multiple raised slightly erythematous papules and small plaques; no similar lesions are noted elsewhere on the body.
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Verruca plana, also called flat warts, are caused by the human papillomavirus of genotypes 3 and 10.1 These lesions are flat-topped and skin-colored to erythematous papules.2 The skin texture of verruca plana is smooth as compared with verruca vulgaris. Autoinoculation may result in a linear configuration and hundreds of lesions may dot the skin surface.
Common locations of infection include the face, dorsum of the hands, and shins. Children are most frequently affected by verruca plana. In adults, the condition may be seen in patients who are immunocompromised and patients with HIV. Infection with verruca plana has been documented following a tattoo application.3 Histologic findings reveal epidermal hyperkeratosis, acanthosis, and a characteristic cluster of vacuolated cells known as koilocytosis.
Verruca plana may resolve spontaneously over a period of months to years. Many cases, however, prove refractory to therapy. Treatment modalities for verruca plana include cryotherapy; photodynamic therapy; topical application of podophyllotoxin and imiquimod; and laser ablation. A recent case report documents the clearing of warts following administration of nonavalent human papillomavirus vaccine.4
Sara Mahmood, DPM, is a podiatrist who completed a joint dermatology/podiatry fellowship and is on staff at DermDox Dermatology Centers in Pennsylvania. Stephen Schleicher, MD, is director of the DermDox Dermatology Centers, associate professor of medicine at Geisinger Commonwealth Medical College, and clinical instructor of dermatology at Arcadia University and Kings College.
1. Eksomtramage T, Aiempanakit K. Verruca plana mimicking seborrheic keratosis in the elderly: a case report. IDCases. 2019;18:e00661. doi:10.1016/j.idcr.2019.e00661
2. Kim WJ, Lee WK, Song M, et al. Clinical clues for differential diagnosis between verruca plana and verruca plana-like seborrheic keratosis. J Dermatol. 2015;42(4):373-377. doi:10.1111/1346-8138.12760
3. Chen YJ, Nabi O, Diao P, Wan RY, Li L. Verruca plana on a tattoo: a case report. Medicine (Baltimore). 2020;99(15):e19744. doi:10.1097/MD.0000000000019744
4. Johnson NM, Pickard CM. Resolution of diffuse facial verruca plana following nonavalent human papillomavirus immunization. Pediatr Dermatol. 2020;10.1111/pde.14384. [Online ahead of print] doi:10.1111/pde.14384