Two cases of multiple Spitz nevi: Correlating clinical, histologic, and fluorescence in situ hybridization findings

Background: The occurrence of multiple Spitz nevi is rare, especially the disseminated variant. Multiple Spitz nevi may be confused with, and must be differentiated from, primary spitzoid melanoma and cutaneous melanoma metastases. Over the past decade, fluorescence in situ hybridization (FISH) has emerged as a tool for studying melanocytic neoplasms, helping to differentiate between melanoma and benign melanocytic nevi. We describe 2 cases of patients with multiple Spitz nevi and their FISH results. Observations: One case of disseminated Spitz nevi, in a 17-year-old female, showed balanced tetraploidy using FISH, while the other case, in a 51-year-old female with multiple Spitz nevi, showed normal diploid cells without significant gains or losses in chromosomes 6 or 11. Conclusions: Patients may present with multiple, even disseminated, Spitz nevi. This phenotype should not be confused with melanoma and/or cutaneous metastasis. The use of FISH studies in context with careful correlation of clinical features and dermoscopic and histologic findings can assist in the diagnostic workup.