ABD Mohs Surgery common mistakes
ABD Mohs Surgery · Understand the traps and how to avoid them.
Treating the Mohs stage count as the definitive adequacy criterion and stopping when margins appear clear on the last stage without confirming that the entire peripheral and deep margin of the debulked specimen was actually examined (i.e., accepting an incomplete margin map).
Candidates conflate 'no tumor seen on the slides I looked at' with 'the whole margin was processed and reviewed'; tissue flattening artifacts and missed quadrants go unrecognized under time pressure.
What to do instead
Before declaring a stage clear, verbally reconstruct the margin map: enumerate each peripheral clock-face segment plus the deep margin and confirm a corresponding slide exists and was reviewed; practice mapping on unknown specimens.
Misidentifying normal structures as tumor on frozen sections - calling eccrine ducts, sebaceous lobules, follicular epithelium, peripheral nerve, or crushed inflammatory cells 'basaloid tumor nests'.
Frozen-section artifact (freezing chatter, crush, edema) distorts adnexal structures, and candidates lack a disciplined comparison of lesional cells against adjacent known normal structures.
What to do instead
Adopt a systematic checklist: assess nuclear features, peripheral palisading, clefting, mucin, and stromal retraction; when uncertain, trace the structure to its duct or follicle of origin; review a teaching set of benign mimics on frozen sections.
Choosing Mohs for a tumor where it is not indicated (e.g., a well-demarcated low-risk nodular BCC in a young patient on a non-critical site) or failing to recognize a scenario where Mohs is clearly indicated (recurrent tumor, ill-defined borders, critical anatomic site, morpheaform histology).
Candidates memorize 'Mohs is best' as a slogan rather than applying appropriateness criteria (recurrence risk, tissue conservation value, histologic subtype, anatomic location).
What to do instead
Build a two-column decision table (Mohs vs. wide local excision vs. other) keyed to tumor subtype, size, site, primary vs. recurrent status, and immunosuppression; rehearse borderline vignettes aloud.
Planning a reconstruction without first defining the defect's anatomic subunits, laxity reservoirs, and neurovascular structures at risk, resulting in a flap or graft that crosses cosmetic subunit boundaries or places a pedicle over a named nerve.
Candidates jump to a familiar flap (e.g., bilobed, rhomboid) before fully characterizing the defect and the regional anatomy.
What to do instead
Use a fixed preoperative worksheet: subunit boundaries, defect dimensions/depth, adjacent laxity, named nerves/vessels, and donor site morbidity; then select the simplest option that respects subunit principles.
Misjudging the vascular territory and pedicle course of a local flap on the face (e.g., assuming a random-pattern flap will survive across a subunit or failing to identify the temporal/supraorbital/supratrochlear neurovascular bundles).
Candidates memorize flap names without internalizing the axial versus random blood supply and the surface landmarks of named vessels.
What to do instead
Study each commonly used facial flap with its pedicle, angiosome, and danger zone drawn on a face diagram; practice marking landmarks (e.g., temporal artery, marginal mandibular nerve) on standardized templates.
Under-documenting the preoperative assessment - omitting anticoagulation status, allergy details, prior radiation, immunosuppression, or the specific consent discussion of recurrence risk and cosmetic outcome.
Candidates treat documentation as boilerplate and rush through the history to get to the procedure.
What to do instead
Use a structured preoperative checklist and a consent script that explicitly covers recurrence, scarring, nerve injury, and alternatives; practice writing a complete note from a vignette.
Failing to recognize and manage an intraoperative or postoperative complication appropriately - e.g., misattributing brisk bleeding to 'normal oozing' when a named vessel is involved, or dismissing a expanding hematoma or signs of infection.
Candidates lack a graded response algorithm and default to reassurance rather than escalation.
What to do instead
Memorize a complication triage algorithm (identify vessel, control, assess airway/compartment, antibiotics vs. drainage vs. return to OR) and rehearse with case vignettes.
Ignoring practice-management and quality metrics - e.g., not knowing how to interpret Mohs stage counts, recurrence tracking, turnaround time, or appropriate use of the Mohs appropriate-use criteria in a quality-improvement context.
Candidates focus exclusively on clinical content and treat the practice/quality domain as filler.
What to do instead
Review the Mohs appropriate-use criteria and core quality indicators; practice interpreting a simple dashboard (stages per case, recurrence rate, frozen-section concordance) and proposing a QI intervention.
Failing to apply ethical and professionalism principles to realistic scenarios - e.g., accepting a case outside one's competence, inadequate informed consent, or mishandling a conflict of interest or a patient's request for unnecessary surgery.
Candidates answer ethical vignettes by intuition rather than applying a framework (beneficence, nonmaleficence, autonomy, justice, scope of practice).
What to do instead
Practice a four-principle framework on vignettes and articulate the specific professional obligation (refer, disclose, document, or decline) rather than a generic 'do what's best'.
Misapplying cutaneous tumor biology - e.g., assuming all BCCs behave identically, overlooking perineural invasion risk in squamous cell carcinoma, or failing to correlate histologic subtype (morpheaform, basosquamous, desmoplastic) with subclinical extension.
Candidates memorize histologic names without linking subtype to biologic behavior and margin requirements.
What to do instead
Create a subtype-to-behavior table (growth pattern, subclinical extension, perineural risk, metastatic potential) and apply it to margin-planning vignettes.