Prevalence, incidence density and standardized morbidity rate of melanoma among patients with congenital melanocytic nevi: A systematic review

Abstract Congenital melanocytic nevi (CMN) are the result of aberrations in the mitogen-activated protein kinase signal transduction pathway. The risk of melanoma is the most important concern among patients with CMN for its poor prognosis. However, due to the great variability between studies, the reported risk of melanoma varied considerably, making it difficult to provide reliable information. To evaluate the prevalence, incidence density and standardized morbidity ratio (SMR) of melanoma among patients with CMN, we conducted a systematic literature search of studies providing data on the risk of melanoma in CMN patients following our registered and published protocol (PROSPERO ID# CRD42022383009). Overall, twenty-seven studies with a total of 11480 CMN patients and 82 melanoma cases were included for analysis. The prevalence of melanoma was 1.84% [95% confidence interval (CI) 1.13%-2.99%] in CMN patients and 2.73% (95% CI 1.67%-4.33%) in patients with large CMN (LCMN). The incidence density of melanoma was 237.56 (95% CI 97.79-575.96) per 100,000 person-years (P-Y) in CMN patients and 585.73 (95% CI 315.39-1085.29) per 100,000 P-Y in the LCMN subgroup. The SMR of melanoma was 122.27 (95% CI 11.84-1262.88) among all CMN patients and 285.97 (95% CI 50.65-1614.59) in patients with LCMN. Our research suggests that the risk of melanoma in the CMN population seems to be overestimated by previous studies, but still significantly higher than that in the normal population. In addition to the risk of melanoma, aesthetic improvement and mental health should also be taken into account when making management decisions.