Melanocytic hyperplasia associated with surgical scars in basal cell carcinoma re-excision specimens: A single-center retrospective study.

ABSTRACT

BACKGROUND: Melanocytic hyperplasia (MH) overlying surgical scars has been reported but MH adjacent to the scar has not been previously addressed. METHODS: We evaluated scar-associated MH in 489 re-excision specimens of basal cell carcinoma. Melanocytic density, confluence, atypia, suprabasal scatter, follicular extension, distance from the scar, correlation with clinicopathologic parameters, and PRAME expression were recorded. RESULTS: One hundred seventy-seven of 489 (36%) cases exhibited MH beyond the scar extending to 6.65 mm median distance, with a median density of 13 melanocytes/0.5 mm (6-24 mm), confluence in 74 (42%) cases, atypia in 14 (8%), suprabasal melanocytes in 25 (14%), and follicular extension in 21 (12%). Mean age of MH group was significantly lower than non-MH group (P < 0.0001). MH overlying the scar was significantly higher in specimens with elastosis than those without elastosis (P < 0.0001). PRAME expression was absent in 14 of 20 cases and present in rare melanocytes in 6 cases. CONCLUSIONS: Increased melanocytic density with confluence, mild atypia, suprabasal scatter, and superficial follicular extension may be observed in re-excision specimens adjacent to surgical scars in the absence of a melanocytic neoplasm. These observations are helpful for appropriate interpretation of melanoma re-excision specimens, to avoid potential pitfalls in diagnosis and unnecessary therapeutic measures.