Abstract: Objective To study the clinicopathologic characteristics of dysplastic nevus.Methods The specimens from 11 patients with dysplastic nevus were studied for their histological characteristics using haematoxylin and eosin staining,and the patients were analyzed for their clinical manifestations.Results Among the 11 patients,7 had multiple lesions while the remaining 4 had single lesion.Of the 11 studied lesions,8 had a diameter ≥5 mm;4 had an obscure margin;6 had an irregular shape;4 were irregularly pigmented;6 displayed an erythematous base.Skin biopsy demonstrated that 3 cases were junctional nevus and 8 were compound nevus.Lentiginous proliferation along the dermal-epidermal junction was observed as a typical histological pattern of all cases.The nevus cells proliferated irregularly and tended toward confluence,forming an appearance of “bridging”.Atypical melanocytes spread subepidermally in a pagetoid manner.Extensive proliferation of melanocytes at the epidermal-dermal junction was observed,with some cells extending beyond the dermal nevus component.Cytological criteria for melanocytic atypia included a nucleus,which was polymorphous and larger than that of a keratinocyte,presence of nucleoli,and hyperchromasia as well as variation in nuclear staining.Conclusions It is important to evaluate the relationship between the histopathologic characteristics and clinical phenotypes of dysplastic nevus,which cannot be diagnosed only based on the atypia of its histological appearance.

Key words: Nevus, Diagnosis, Pathology