Diagnostic Change From Atypical Intraepidermal Melanocytic Proliferation to Melanoma After Conventional Excision—A Single Academic Institution Cross-Sectional Study

BACKGROUND: Atypical intraepidermal melanocytic proliferation (AIMP) is a histopathologic diagnosis with uncertain malignant potential and presents a surgical management dilemma for clinicians. OBJECTIVE: To identify the associated clinical and histopathologic factors and the frequency of diagnostic change to melanoma after conventional excision of AIMP. METHODS: Retrospective cross-sectional study of 306 AIMPs treated by conventional excision. RESULTS: Diagnostic change to melanoma occurred in 4.2% (13/306) of AIMP lesions after histopathologic review of the excision specimen; melanomas were in situ in 85% (11/13) and invasive in 15% (2/13) of cases. Factors associated with diagnostic change to melanoma included anatomic location on the head and neck (Odds ratio OR 8.49, 95% confidence interval CI 2.17, 33.19; p = .001) and acral areas (OR 9.24, 95% CI 2.18, 39.24; p = .001), lesion extension to the base of the biopsy specimen (OR 13.07, 95% CI 2.98, 57.31; p = .001), biopsy using the punch technique (OR 6.06, 95% CI 1.95, 18.86; p = .013), and melanoma in the initial biopsy's histopathologic differential diagnosis (OR 13.29, 95% CI 1.71, 103.57; p = .001). CONCLUSION: Preoperative counseling and surgical planning for AIMP should be individualized to account for potential diagnostic change to melanoma, especially when specific risk factors are present.