Non-multiple medium-sized congenital melanocytic nevi: to excise or to follow up?

Congenital melanocytic nevi (CMN) are benign lesions composed of clonal proliferations of melanocytes. Although medium-sized CMN are common and generally remain benign throughout a person's lifetime, they may be precursors of melanoma. There is a limited number of studies focused on the risk of melanoma in solitary, medium-sized, congenital melanocytic nevus; therefore, the incidence of malignant transformation and guidelines for treatment are not well established.

Prompted by the limited data, we conducted this study to gather more information about medium-sized CMN, to optimize clinical care. We share our analysis of surgically removed medium-sized CMN.

A total of 10 patients with non-multiple, medium-sized, congenital melanocytic nevus were included in this study. Lesions were removed using surgical procedures.

In most of the cases the reason for excision of the medium-sized CMN was evolution of the lesion or aesthetic considerations reported by the patients. In 2 cases, due to the large size of the lesions, serial excisions were performed, while other CMN were removed surgically using simple excision technique. Eight of 10 medium-sized CMN were histologically described as benign, and 2 cases of malignant transformations were reported.

According to our clinical experience and knowledge, we recommend managing patients on an individual basis, taking into consideration multiple clinical attributes. In our opinion, long-lasting observation is the management of choice, and if there is need of surgery, we recommend total simple or staged excision depending on nevus size.