P23 Primary penile melanoma and penile lichen sclerosus

The association between squamous cell malignancies and genital lichen sclerosus (GLSc) is well established. There is an increasing literature regarding the relationship of GLSc with genital malignant melanoma (MM). While there have been several reported cases of vulvar melanoma associated with lichen sclerosus (LSc), there have been fewer cases published with regard to male genital (M)GLSc and penile (Pe)MM. The aims of this study were to explore the relationship between PeMM and MGLSc by reviewing all cases managed by our multidisciplinary service over a period of 11 years. All patients known to our tertiary urology and male genital dermatology service with a diagnosis of penile MM and where histology was available for review were identified over an 11-year period (2011–2022). Two independent dermatologists reviewed the clinical records and photographs where available. Two independent mutually blinded histopathologists reviewed the histology and recorded features of GLSc where present. In cases of discordance between histopathologists, a third independent histopathologist reviewed the cases. Eleven patients were identified for inclusion in the study. Overall, GLSc was present on histopathology in nine of 11 cases (82%). Findings were concordantly positive in five cases and concordantly negative in one case. In cases with discordant findings (n = 5), the third histopathologist determined GLSc to be present in four cases and absent in one case. Clinical photographs were available for three cases and clinical features of GLSc were seen in all of them; they also all had positive histopathological findings. Clinical notes, including electronic notes and letters, were available for review in eight cases. Symptoms in keeping with GLSc were mentioned in only one case, and signs suggestive of GLSc were documented in three cases. Penile MM is a rare entity accounting for 0.7% of penile cancer and 0.1% of MM cases. Like other malignancies, MM is a multifactorial disease caused by a combination of environmental factors and altered host responses contributing to an alteration of regulatory processes. Although ultraviolet exposure is important in the pathogenesis of extragenital MM, this cannot be a factor for genital disease. However, specific risk factors for genital MM have not yet been elucidated. To our knowledge, there have only been three previously documented cases (all from our group) of PeMM coexisting with GLSc. This present study finding of GLSc in 9 of 11