Spitz Nevi and Other Spitzoid Neoplasms in Children: Overview of Incidence Data and Diagnostic Criteria.

Spitz nevi are benign melanocytic neoplasms characterized by epithelioid or spindle melanocytes or both. In some rare cases their presentation overlaps with the clinical and histopathologic features of malignant melanoma, so a differential diagnosis can be difficult to make. Intermediate forms between Spitz nevi and malignant melanoma, with unpredictable behavior, have been called atypical Spitz tumors. A literature search was performed to review the clinical, dermoscopic, genetic, and histopathologic aspects of spitzoid tumors. Spitz nevi mainly occur in children, with no predilection for sex, and in young women. Common sites are the head and lower arms, where Spitz nevi present as pink nodules or hyperpigmented plaques. Spitzoid lesions may have diverse dermoscopic patterns: vascular, starburst, globular, atypical, reticular, negative homogeneous, or targetoid. The management of spitzoid lesions can be invasive or conservative; surgical excision is usually reserved for those with doubtful features, whereas clinical and dermoscopic follow-up is preferred for typical pediatric Spitz nevi. The role of sentinel lymph node biopsy in atypical Spitz tumors is debated. Immunohistochemistry and new molecular techniques such as comparative genomic hybridization, polymerase chain reaction, and fluorescence in situ hybridization offer new diagnostic perspectives, investigating genetic alterations that are specific for malignant melanoma or for Spitz nevi.