The role of TERT promoter mutations in differentiating recurrent nevi from recurrent melanomas: A retrospective, case-control study

Background: Repigmentation at previous biopsy sites pose a significant diagnostic dilemma given clinical and histologic similarities between recurrent nevi and locally recurrent melanoma. Though common in melanoma, the role of TERT promoter mutations (TPMs) in recurrent nevi is unknown. Objective: We investigated the role of TPMs in recurrent nevi and whether the presence of hotspot TPM distinguishes recurrent nevi from locally recurrent melanoma. We also characterized clinical and histologic features differentiating these lesions. Methods: We analyzed 11 locally recurrent melanomas, 17 recurrent nevi, and melanoma and nevus controls to determine TPM status. We also assessed clinical and histologic features of the recurrent groups. Results: Hotspot TPMs were more common in recurrent melanomas than recurrent nevi (P =.008). Recurrent melanomas were more likely to have solar elastosis (P =.0047), multilayering of melanocytes in the epidermis (P =.0221), adnexal involvement (P =.0069), and epidermal consumption (P =.0204). Recurrent nevi had intra-epidermal atypia limited to the area above the scar (P <.0001) and occurred earlier after the original biopsy (P <.0008). Solar elastosis, months to recurrence, and hotspot TPMs were independently associated with recurrent melanoma in multivariate analysis. Limitations: This was a retrospective study. Conclusion: Hotspot TPMs are significantly more frequent in recurrent melanomas and could serve as a diagnostic clue in histologically ambiguous cases.