The criteria that define borderline melanocytic tumor (BMT) were clarified in a study in 32 BMT patients (aged 3-58 years). Four categories of BMT were recognized: i) nevoid BMT (n = 4); ii) atypical Spitz tumor (n = 14); iii) pigmented epithelioid melanocytoma (n = 7); and iv) deep penetrating nevus (n = 7). The percentage of patients with positive sentinel lymph nodes in these categories ranged from 14-57%, the highest frequency being in the deep penetrating nevus group. The mean follow-up was 4.2 years and one patient (36 years, male) died in the deep penetrating nevus group (Magro, C.M. et al. J Am Acad Dermatol 2010, 62(3): 469).