Histologic pitfalls in the Mohs technique.

The success of the Mohs procedure depends on the reliability of each step in the technique. Pitfalls in histologic preparation of the tissue specimens may occur during debulking, excising, orienting, creating the map, sectioning, inking, tissue flattening and freezing, cutting, slide fixation, staining, and mapping the tumor. Challenges are also present in interpreting the slides. Diagnostic pitfalls include floaters, inflammatory conditions resembling tumor, and perineural invasion. The technique requires time, teaching, and a sufficient quantity of cases from which to learn, as well as attention to the pitfalls that occur while processing tissue specimens and interpreting and mapping the histology.