On the Definition of Mohs Surgery and How It Determines Appropriate Surgical Margins

Mohs Micrographic Surgery Local Recurrences

“…Mapping errors include misoriented specimen relative to the patient and/or map and incorrectly inked specimen with reversal of colors. Tumors in difficult anatomic locations such as the ear or medial canthus and large tumors are especially prone to mapping errors 5,6 . In our retrospective study, only certain surgical or mapping errors were amenable to examination.…”

“…There may be holes in the sections (Figure 7) due to incomplete or too thin a layer. In addition, tumor, cartilage or fatty tissue drop‐out may create holes in the sections 5,11 . The most distressing finding is a hole in the specimen caused by tumor drop‐out.…”

“…Finally, tumor biology may account for skip areas such as is seen in melanoma regression, sebaceous carcinoma, Paget's disease, and perineural spread of cutaneous squamous cell carcinoma 5,14,15 . In these cases, an additional layer should be taken after a “negative” layer has been obtained.…”

“…This local recurrence rate should be amenable to further reduction if correctable technical problems play a factor. Recent editorials have considered all of the theoretically possible reasons for MMS recurrence, 5,6 but a systematic study of patients has so far been lacking. This retrospective study was undertaken to determine what technical factors, if any, may have contributed to local tumor recurrence after presumably curative MMS.…”

Facing the Block and False Positives in Mohs Surgery: A Retrospective Study of 2,198 Cases

“…Although facing is a known source of false positives, the rate of false positives attributable to excessive tissue trimming is unknown . Lear and colleagues studied the average depth of trimming required to obtain a complete section using four techniques: glass slide, a commercial method, float, and heat sink .…”