A clinical, histologic, and follow-up study of genital melanosis in men and women: Beyond the Abstract

Genital melanosis, a rare condition often characterized by large, asymmetrical and often mutli-focal pigmentation occurring on genital skin, is often mistaken for genital melanoma. As the literature on the topic is limited, management of these patients is often very difficult as little is known about the risk for progression to gential melanoma.  Although lesions biopsied from patients with genital melanosis show benign histologic features, providers may opt for further excisional procedures due to the concerning clinical appearance of these lesions and uncertainty about future melanoma risk. 

In this study, we provide clinical, histologic and follow up data for 41 patients diagnosed with genital melanosis. Of the 38 cases with detailed clinical information available, 17 patients had lesions that were described as irregular in either shape or color and 22 had lesions with at least two different colors, including shades of brown and black, blue/grey discoloration and/or areas of hyper or hypo pigmentation. Nineteen patients had multiple lesions on clinical exam. 

Despite the concerning clinical appearance of these lesions, none of the 30 patients with clinical follow up were found to develop genital melanoma after a diagnosis of genital melanosis after an average of 30.5 months of follow up (range 3-115 months). One patient developed genital melanosis 10 years and 9 months after a diagnosis of genital melanoma. Additionally, of the 23 patients with detailed dermatologic follow up, a majority either saw complete resolution (n=10) or no evidence of change in their lesions (n=9) with only two patients with recurrences after re-excision. 

Patients in which genital melanosis demonstrated the following histologic findings: suprabasal melanocytes and/or a higher melanocyte count (assessed via a Sox10 count) had a higher likelihood of melanoma at other body sites than those with histologically bland appearing genital melanosis. Although our sample size was small, our follow up data indicates that most patients diagnosed with genital melanosis can be followed with close clinical follow up rather than further surgery in a delicate anatomical site in addition to careful TBSE for the possibility of melanoma of another body site. If there is an association between genital melanosis and genital melanoma, the increased risk is likely small and difficult to precisely quantify. 

Read the Abstract

Written by Alexandra M. Haugh and Jeffrey A. Bubley