Histopathological features of acral melanocytic nevi in children: study of 21 cases

Benign melanocytic lesions in children may give cause for some concern histologically. This is because they represent a specific entity, or they reflect the state of evolution of the lesion or the anatomical location. This latter phenomenon has been poorly documented in children. In this study, we address the problem of atypical features frequently seen in benign nevi from acral sites in a group of patients aged 18 years or less. Twenty-one cases (12 female, 9 male) were identified from the Department of Pathology files during the years 1975-1988. All were Caucasian. Histological examination revealed that 6 cases were congenital and 15 were acquired; of these, 19 cases (90%) had a junctional component and all of these exhibited architecture atypia in the form of either lentiginous proliferation (84%) or confluence of junctional nests (84%). Forty-two percent (8/19) showed a mixture of both. Thirty-seven percent (7/19) exhibited transepidermal elimination of melanocytic nests, with 13/19 (68%) showing single cell infiltration of the epidermis. Atypical size, shape, and location of the junctional nests were present in 10/19 cases (53%). Within this group there appears to be no relationship between the age of the patient and the degree of architectural atypia. Mild cytological atypia was common. This report stresses the importance of anatomic subsite in the assessment of melanocytic lesions in children as well as in adults.