The clinical and dermatoscopic features of penile pigmentation in men with genital lichen sclerosus.

Background: Benign male genital pigmentation is a confusing field with poorly defined terminology. This entity is frequently encountered in our male genital lichen sclerosus (MGLSc) cohort and suggests an association with prior inflammation, however there is a limited literature on the topic. Objectives: This paper describes the attributes of 21 patients with MGLSc and features of benign genital pigmentation, reviews the existing literature on benign male genital pigmentation and makes recommendations for better practice. Methods: We prospectively identified 21 patients with MGLSc and clinical diagnoses of benign penile pigmentation who attended specialist male genital dermatoses clinics. Relevant findings were abstracted from clinical notes, outpatient letters, medical photographs, dermatoscopic images and histological reports. Results: The clinical features of this cohort are discussed and the dermatoscopic images analysed. 15 of 21 patients were followed up for over 2 years and all of these had stable appearance of pigmentation. 87% reported pigmentation to have emerged after the onset of MGLSc symptoms, with latency ranging from one to over 25 years. The terms lentiginosis, melanosis, and post-inflammatory hyperpigmentation are discussed in context of the existing literature. Conclusions: We propose that genital lentiginosis and melanosis are clinically indistinguishable macroscopically and are on a clinical and histopathological spectrum. Although there is a compelling narrative that genital melanosis is most often truly benign, there is also emerging evidence to suggest an increased risk of penile melanoma in patients with MGLSc. Furthermore, pigmented lesions in MGLSc can portray concerning morphological features even when benign. A low threshold for biopsy and follow-up is thus warranted.