By Gary M. White, MD
Penile intraepithelial neoplasia (PIN) is an overarching term that encompasses 3 premalignant penile lesions: Bowen disease, erythroplasia of Queyrat (shown above), and Bowenoid papulosis. These clinical variants all show features of squamous cell carcinoma in situ histologically.
Bowen disease typically presents as a well-demarcated, scaly plaque on keratinized penile skin. Erythroplasia of Queyrat is characterized by moist, red plaques located on the mucosal surfaces of the glans and prepuce. Finally bowenoid papulosis typically presents with multiple, flesh-colored papillomatous papules on the penile shaft, glans, or foreskin.
Surgery, if possible, is the gold standard. However, significant morbidity can occur and medical interventions are often employed initially. These include cryotherapy, topical 5-fluorouracil (5-FU), and imiqimod, either as monotherapy or in combination.
In one report [JAAD Case Reports 2017;3;546], good results were obtained with cryotherapy (2 freeze/thaw cycles consisting of 10 seconds of funneled spray application of liquid nitrogen per lesion per cycle) followed by at-home treatment with topical imiquimod 3 to 5 times a week for at least 8 weeks. The average number of cryotherapy sessions was 5.1. The average number of months using topical imiquimod was 7.8 months. Patients were instructed to wait at least 3 to 4 days after cryotherapy before applying the imiquimod, and to use hydrocortisone and skin moisturizer during the treatment period to ameliorate any skin irritation. All 8 patients exhibited a complete response to therapy. During the follow-up period (range 5-59 months), none of the patients exhibited signs of recurrence.