Clinical and dermoscopic features of atypical Spitz tumors : A multicenter, retrospective, case-control study

Background Few studies have described the clinical and dermoscopic features of atypical Spitz tumors. Objective We sought to describe the clinical and dermoscopic features of a series of atypical Spitz tumors as compared with those of conventional Spitz nevi. Methods This was a multicenter, retrospective, case-control study, analyzing the clinical and dermoscopic characteristics of 55 atypical Spitz tumors and 110 Spitz nevi that were excised and diagnosed histopathologically. Results The majority of atypical Spitz tumors presented clinically as a plaque or nodule, dermoscopically typified by a multicomponent or nonspecific pattern. A proportion of lesions (16.4%) exhibited the typical nonpigmented Spitzoid pattern of dotted vessels and white lines under dermoscopy. Nodularity, ulceration, linear vessels, polymorphic vessels, white lines, and blue-white veil were associated with atypical Spitz tumors by univariate analysis, but only nodularity and white lines remained significant after multivariate analysis. In contrast, a pigmented typical Spitzoid pattern was a potent predictor of Spitz nevi, associated with 6.5-fold increased probability. Limitations Differentiation from Spitzoid melanoma and other nonmelanocytic lesions was not investigated. Conclusion Atypical Spitz tumors are polymorphic melanocytic proliferations with a nodular clinical appearance. Dermoscopically they demonstrate a multicomponent and nonspecific pattern. A typical nonpigmented Spitzoid pattern on dermoscopy (with dotted vessels and white lines) does not exclude atypical Spitz tumors.