The Accuracy of 2.5 mm Punch Biopsy in theDiagnosis of Skin Lesions

Background: Punch biopsies are gaining widespread attention among medical professionals for their broad use and ease of access. Despite decades-long use, there needs to be more robust statistical evidence regarding their diagnostic accuracy. This study aims to evaluate the accuracy of the 2.5 mm punch biopsy in diagnosing skin lesions by comparing the histopathology of punch biopsies with that of excisional biopsies. Methods: In this retrospective study, a review of 4,000 charts, including skin lesions seen by a single plastic surgeon from 2016–2023, was conducted to identify patients who underwent a 2.5 mm punch biopsy of a lesion followed by a subsequent excisional biopsy. 206 charts were identified. Concord ance between punch and excisional histopathologies was used to calculate the efficacy of the 2.5 mm punch biopsy as a diagnostic tool. Results: Of 206, 141 skin lesions were characterized as cancerous by punch biopsy, all confirmed on subsequent excisional biopsy. 51 were deemed benign/precancerous on punch biopsy and confirmed by excision. 12 were identified as cancerous by punch biopsy but later characterized as benign/precancerous by excision. 2 were characterized as precancerous by punch biopsy and cancerous by excision. Analysis revealed that the 2.5 mm punch biopsy had a sensitivity of 98.6% (95% CI: 95.04%–99.83%) and specificity of 80.95% (69%–89.75%) in diagnosing skin lesions, which is statistically significant by several measures. Conclusion: The 2.5 mm punch biopsy is an accurate tool for diagnosing skin lesions. It can be applied to various anatomical sites and lesion sizes. Its non-suturing requirement may enhance cosmetic outcomes and ease-of-use.