Anatomic mapping and clinicopathologic analysis of benign acral melanocytic neoplasms: A comparison between adults and children

BackgroundThe clinicopathologic features of benign acral melanocytic neoplasms (BAMNs) remain poorly understood.ObjectiveTo define the clinicopathologic features of BAMNs.MethodsWe analyzed clinical data and mapped BAMNs anatomically. We also reviewed the histopathologic features of BAMNs and compared these between adults and children.ResultsWe included 396 cases of BAMN: 335 adults and 61 children (376 acquired and 20 congenital lesions). Anatomic mapping revealed that the nonweight-bearing portion of the foot was the most common site in adults (120/335, 35.8%) and the forefoot the most common site in children (17/61, 27.9%) for BAMNs. The long axes of the BAMNs paralleled the dermatoglyphic lines on the palms and soles, as did most tissue sections. The lesion diameters were <5.7 mm in all acquired lesions. Histopathologically, we diagnosed 69 lentigo simplex, 201 junctional, 114 compound, 8 intradermal, and 4 blue nevi. Corneal pigmentation, nests located between rete ridges, dendrite prominence, and cytologic atypia were all significantly more common in children than adults.LimitationsThe retrospective study design and acquiring patients from a single institution of a single country limited the research results.ConclusionBAMNs develop most commonly on nonweight-bearing regions of the soles in adults and on the forefoot in children. The long axis of the lesion follows the dermatoglyphics, and cytologic atypia is more common in children.