Clinicopathological features of malignant melanoma arising from small and medium-sized congenital melanocytic nevi = Clinicopathological features of malignant melanoma arising from small and medium-sized congenital melanocytic nevi

다국어 초록 (Multilingual Abstract)

Background: Unlike giant congenital melanocytic nevi (CMN), small and medium-sized CMN (smCMN) are not generally considered as a precursor lesion for malignant melanoma (MM), but we often confront MM arising from smCMN in a clinical setting.
Objectives: The purpose of this study is to investigate clinicopathological features of MM arising from smCMN and to compare their features with non CMN-MM.
Methods: A retrospective study has been conducted based on the medical records of patients with MM arising from smCMN from 2011 to 2017. Their sex, age, Breslow thickness (BT), type of melanoma and metastasis were identified and these findings were compared with those of invasive MM arising from non CMN skin.
Results: MM was found in 10 of 380 (2.6%) smCMN and they comprised 10 of 121 (8.3%) total invasive MM of the same period. They developed more in female and showed earlier onset age (49.2 years), thinner mean BT (4.7mm) than those of non CMN-MM (62.8 years, 5.7mm, respectively). Most of them were nodular melanoma (80.0%). The rates of nodal and distant metastasis (20%, 0%) were both lower than those of non CMN-MM (27.0%, 4.5%, respectively).
Conclusion: MM occurred at a relatively higher frequency than expected in smCMN which should also be paid more attention to prevent delay in the treatment of potential MM. Limitation: This is a single center study done by small number of patient from a university-setting hospital.