Spitzoid tumors in children and adults: a comparative clinical, pathological, and cytogenetic analysis.

Spitzoid neoplasms may represent a difficult diagnosis in the practice of dermatopathology. We evaluated the concordance of the fluorescence in-situ hybridization (FISH) assay, histopathology, and dermoscopy in a group of adults and in a group of children with spitzoid neoplasms. The FISH assay, designed to detect the copy number of the RREB1 (6p25), MYB (6q23), and CCND1 (11q13) genes and of centromere 6 (Cep 6), was performed in a group of children and in a group of adults with a histopathologic diagnosis of spitzoid neoplasms. FISH data were compared with dermoscopy and histopathology. Fifteen spitzoid neoplasms were collected from 13 patients (five children and eight adults): nine lesions were histologically diagnosed as typical Spitz nevi; three lesions were melanomas and three were atypical Spitz nevi. The conventional FISH criteria were concordant with the clinical and histopathologic diagnosis of Spitz nevi in four adults and in three children. FISH criteria of the other neoplasms showed a concordance with the histopathologic diagnosis in three cases. Discordant results were obtained in five cases (two children, three adults). The FISH melanoma assay proved more reliable in spitzoid lesions found in adults than in children. This assay should be interpreted carefully in pediatric patients with Spitz nevi in the context of histological features as melanomas in the pediatric population may show distinct chromosomal aberrations.