Congenital malignant melanoma: An Integrated Clinicopathological Clinical Case Series

Abstract

Abstract Background Congenital malignant melanoma (CMM) is present at birth or in the first year of life. It arises through transplacental, de novo, or is associated with congenital melanocytic nevus (CMN). CMM is rare, and its relevant data is limited. Here, we describe 14 cases of congenital malignant melanoma and retrospectively analyze the clinicopathological and molecular features of this entity. Methods Clinical data of patients were retrieved, and immunohistochemistry (IHC) and molecular analyses were performed. Besides, a systematic review of articles was conducted using PubMed, and these screened cases were analyzed in EndNote. Results Our series comprised six CMN-associated melanoma, six de novo CMM, and two transplacental metastatic melanoma. Histologically, the epithelioid cell was the most common feature in 54% of cases. Spindle and atypical cells were observed in 15% and 23%, respectively. NRAS mutations were detected in 75% of cases, and one patient showed abbreviations in four-probe analyses. Patients ranged in age from in-utero to 12 months, with an average age of 3.5. Males were predominant with a male to female ratio of 2.5:1. Scalp was the most affected location (n = 7), with the most common symptoms being mass. After a median overall survival of 18.5 (ranging from 0.7 to 312) months, four patients died of tumor progression. The mortality of de novo and CMN-associated melanoma was 33% and 17%, respectively, while that of transplacental melanoma was 50%. Conclusions Congenital malignant melanoma is a rare subtype of pediatric melanoma associated with poor prognosis. The disease has a high incidence of scalp involvement and male predominance. The epithelioid cell is more common than the spindle and atypical cells. Molecular tests are crucial for the diagnosis of CMM. Due to the rarity, more cases and research are needed to understand the epidemiological features and molecular biology of CMM.