Mohs on the Nose: When to Stop and Reconstruct

Decision framework for an alar defect ~1.9 x 1.6 cm with intact perichondrium and intact alar rim:

• Second intention is a legitimate option for alar defects, especially shallow ones with intact perichondrium; it avoids donor-site and flap risk and can give acceptable contour. However, a defect this size may contract and distort the alar rim or nasal valve, so it is best reserved for smaller or more medial defects.
• Full-thickness skin graft (e.g., preauricular or conchal) is reasonable for a defect with a vascularized bed (perichondrium intact) and preserves local tissue; downside is color/texture mismatch and possible graft contraction.
• Local flap (e.g., nasolabial, bilobed, or alar advancement) gives the best color/texture match but consumes adjacent tissue and can distort the alar rim if poorly planned; a defect near the alar crease risks notching.

Apixaban: do not stop anticoagulation solely for a small dermatologic reconstruction without cardiology input - the thromboembolic risk of interruption in AF often outweighs bleeding risk. Meticulous hemostasis, cautery, and pressure dressings are used; the surgeon accepts a modest hematoma risk. Coordinate with the prescribing clinician if any interruption is contemplated.

Diabetes: A1c 7.1% is reasonably controlled; proceed with attention to glucose in the perioperative period and infection vigilance.

Perichondrium is a barrier: tumor abutting but not invading it means the deep margin is close/at the perichondrium, and frozen-section interpretation at this interface is technically demanding (cartilage artifact, difficulty orienting thin tissue). Implications:

• Margin confidence is lower than a clean fat/muscle margin. Consider whether the perichondrium should be taken as part of the specimen or whether additional tissue should be sampled to confirm clearance.
• If perichondrium is left in place and is the deepest margin, avoid a reconstruction that places a large avascular graft directly over marginally cleared perichondrium without a vascularized bed - graft take depends on the bed, and a compromised bed risks graft failure and obscures recurrence.
• Second intention or a flap with its own blood supply may be safer than a graft if the bed's vascularity is in question.
• Close follow-up for recurrence is essential; document the deep margin status explicitly.

If there is any doubt about deep clearance, discuss further staged excision versus close observation before committing to a complex reconstruction.

A new firm pearly papule at the reconstruction margin raises recurrent BCC as the leading concern, though scar/ suture granuloma, inclusion cyst, or hypertrophic scar are alternatives.

Approach:

• Clinical exam with dermoscopy; document size and relationship to the prior defect.
• Biopsy (punch or shave) for histology - do not assume recurrence or scar without tissue.
• If recurrent BCC is confirmed, re-stage with Mohs if feasible; recurrence in a reconstructed site is more difficult because of altered anatomy and scar tissue, and prior flap/graft can distort planes.
• Review the original Mohs maps and margin status; a deep margin at perichondrium is a known risk factor for recurrence.
• Consider whether the reconstruction obscured the true margin, which is why documenting deep margin status and planning surveillance matters.

Counsel the patient that recurrence after Mohs is uncommon but higher with close deep margins, and that early biopsy of any new papule is warranted.