A reappraisal of the epidemiology of Spitz neoplasms in the molecular era: A retrospective cohort study

Background: Previous studies suggest that Spitz neoplasms occur primarily in younger patients, leading pathologists to shy away from diagnosing a benign Spitz neoplasm in the elderly. With the advent of genomic sequencing, there is a need for reappraisal of the epidemiology of Spitz neoplasms in the modern molecular era. Objective: We aim to reassess the epidemiology of Spitz neoplasms incorporating next-generation sequencing.Methods: We looked at 53,814 non-Spitz neoplasms and 1260 Spitz neoplasms including 286 Spitz neoplasms with next-generation sequencing testing and collected various epidemiologic data. Results: In our general pool of cases, the proportion of Spitz neoplasm cases occurring is relatively the same in each of the first 4 decades of life with a precipitous drop in the fifth decade. In assessing a group of genomically verified cases of Spitz neoplasms, the drop was much less significant and up to 20% of all Spitz neoplasm cases occurred in patients over 50 years of age. Limitations: Limitations included the number of genetically verified Spitz neoplasm cases available and a possible bias as to which cases undergo genomic testing.Conclusion: Genomic verification may allow more confident diagnosis of Spitz neoplasms in patients over 50 years of age and avoid melanoma overdiagnosis. ( J Am Acad Dermatol 2023;89:1185-91.)