A single-institution retrospective evaluation of Mohs incision angles and histopathologic specimen quality.

Background: Traditionally, Mohs layers are excised using a beveled incision to facilitate tissue flattening for tangential sectioning. Some surgeons perform non-beveled incisions; however, these specimens may be harder for the histotechnician to process. Limited data exist comparing slide quality between these techniques.

Methods: Retrospective review of cases performed by two Mohs surgeons (surgeon 1 = non-beveled incision; surgeon 2 =  beveled incision) using different incision angles between June 2014 and December 2016. Daily histopathologic slide quality assessment scores (maximum score = 5, minimum score = 1) of the day's first case were compared.

Results: About 536 slides (surgeon 1 = 277, surgeon 2 = 259) were evaluated from 2,825 cases. Mean quality assessment scores were similar between surgeons (4.89 and 4.86; P = 0.31) with missing or folded epidermis being the most commonly reported issue for both surgeons.

Conclusion: Similar slide quality can be achieved via both beveled and non-beveled Mohs cutting angles. While more relaxing incisions may be necessary to optimize tissue flattening with non-beveled incisions, there is no associated increased loss of epidermal margins. The potential benefits of non-beveled incisions, such as minimizing tangentially cut adnexal structures and creating vertical wound edges optimized for repair, may offer an alternative technique with positive clinical implications.