P092 Congenital melanocytic nevus: a clinicopathologic study and its association with nevus cell types (Type A, B, C)

Background: Congenital melanocytic nevus may be defined as a lesion present at birth and containing nevus cells. Maturation in the melanocytic nevus means a conversion of pigment-producing large, clear type A cells to nerve-like type C cells through lymphocytoid type B cells. Objectives: This study was performed to investigate the clinical and pathologic characteristics of congenital melanocytic nevus and associated factors with nevus cell types in Korean population. Methods: This study was performed with patients histologically confirmed as congenital melanocytic nevus between 2007 and 2015. The proportion and region of interest (ROI) of type A, B and C cells were calculated using ‘image J’ program. Statistical differences were assessed using the Kruskal-Wallis test and Mann-Whitney test. Results: Mean size of nevus was 2.7±2.0 cm, and the most common location of the lesion was head and neck (n=20, 32.3%). Depth of the nevus cell and the nevus cell infiltration to the eccrine gland positively correlate with the proportion of the type C cell to the type A+B cell (p<0.05), and angioadnexocentric nevus was reported at 4 cases (4.84%). Conclusion: As the depth of the nevus cell and the nevus cell infiltration to the eccrine gland increase, the proportion of the type C cell to the type A+B cell markedly increases. Clinicopathologic features of angioadnexocentric nevus identified at this study are identical to previous studies.