Balancing Cure and Cosmesis in Mohs Surgery

The precise margin control and success rates of Mohs micrographic surgery (MMS) position it as a specialized method of treating skin cancers, particularly nonmelanoma types such as basal cell carcinoma and squamous cell carcinoma. It is the most effective treatment for skin cancer today, with the highest cure rate for most skin cancers—up to a 99% success rate.¹ With MMS, the Mohs surgeon functions as both the surgeon and pathologist, working meticulously to ensure successful outcomes and patient safety. Surgical management becomes increasingly complex in tumors in anatomically challenging regions such as the nose, eyelid, lips, scalp, and nails, where functional and aesthetic outcomes are intertwined. Different technical considerations, reconstructive methodologies, and clinical strategies are employed in MMS for these areas. Herein, we discuss each area and present a case vignette.

The Mohs Appropriate Use Criteria chart (Figure) provides guidelines for physicians to determine whether MMS may be appropriate. Criteria used include type of skin cancer, size of skin cancer, subtype of cancer, and whether the tumor is primary or recurrent.² Note that this chart is a guideline, and physicians should use their clinical judgment, experience, and individual patient circumstances when making treatment decisions.

Nose

Reconstruction of nasal defects has challenges due to the interplay of functional structures and aesthetics. The nasal cavity plays a major role in respiration as the entry point for inspired air and possesses key structures to be addressed, such as the internal and external valves that regulate air flow during respiration. The nasal valve is most compromised over the alar crease of the nose. To avoid nasal valve collapse, suspension sutures may be necessary after MMS to prevent airway obstruction.³ Cartilage struts may also be necessary to prevent nasal stenosis. As the focal point of the face, the nose is a cosmetically sensitive area and can be divided into zones of various tissue types and subunits that must be considered during reconstruction. Zone 1 comprises the skin superior to the internal nasal valve and consists of mobile, minimally sebaceous skin. Zone 2 is directly inferior to Zone 1 and consists of thicker, immobile, highly sebaceous skin. Sebaceous nasal skin is more prone to scar spread, scar inversion, infection, and necrosis.⁴ Zone 3 is inferior to Zone 2 and consists of thinner, relatively immobile, minimally sebaceous skin.⁵ The nasal subunit principle divides the nose into 9 subunits and proposes to contain repairs in the subunits already involved by the defect and consider repairing an entire subunit if more than 50% is involved.⁶ The zones and subunits integrate aesthetic and anatomical characteristics and guide surgeons when tackling the challenges that come from the nonuniform qualities of nasal skin during repair.

Eyelid

Undesirable outcomes after eyelid reconstruction, such as ectropion and entropion, can lead to complications such as irritation, sensitivity to light, dry eyes, and excessive tearing.⁷ Paramount when considering reconstruction around the eyelid is to avoid excessive tension on the lower eyelid margin. A surgical technique applicable to various flaps, grafts, and primary closures that may avoid this is periosteal tacking sutures, which anchor tissue to the periosteum of the orbital rim to reduce the vertical stress vectors on the lower eyelid.⁸ Another technique for primary closures is to orient sutures parallel to the eyelid margin, which will also reduce vertical stress vectors on the lower eyelid. Preserving the lacrimal system is crucial to protect tear drainage and prevent epiphora, which can be difficult for defects near the medial canthus. Patients with at least 1 functioning canaliculus may remain asymptomatic, but reconstruction should avoid damaging structures of the lacrimal system when possible.⁹ For defects near the lateral canthus that are too large for primary closures but cover less than 75% of the eyelid margin, a Tenzel semicircular flap may be indicated. After cantholysis and undermining are performed, a flap is advanced to cover the defect.¹⁰ As a free margin, it is important to weigh the risks and benefits of all reconstructive methods due to the uniqueness of the eyelid in terms of its characteristics and functionality. Preserving the functional use and anatomy of the eye is of utmost importance during reconstruction.

Lips

The lips are another free margin that is a focal point of the face and possess unique characteristics. The skin is thin, lacks hair and sweat glands, and is at the boundary of mucosa and facial skin. During repair, it is important to assess the extent of the defect into the mucosa, skin, and muscle. The primary muscle of the lip, the orbicularis oris, allows for various lip movements and extends to the lateral oral commissure. The surgeon should suture the muscle to itself, when possible, to preserve these functions and avoid distortion of the lip and lateral oral commissures, which can lead to drooling or a sneer. In addition, alignment of the vermillion border is important to maintain a natural appearance. Symmetry of the apical triangle should also be preserved, when possible, as asymmetry is more visually noticeable than in other areas of the face and may cause emotional stress to patients.¹¹

Scalp

Scalp defects are often characterized by their size and the reduced elasticity of the underlying tissue. Skin on the scalp is thick, highly vascular, and relatively immobile. Individual scalps vary, though, which plays a role in determining how to repair them. For more minor defects, healing by secondary intention or a linear closure may be appropriate.¹² Tight scalps pose challenges and may require techniques such as a galeotomy to relieve tension. If the defect extends to the periosteum, consider an approach such as a flap to cover the exposed bone when possible or the galeal hinge flap. With it, a reservoir of the galea is dissected and hinged to cover the exposed periosteal defect. A split or full-thickness skin graft may then be used to repair the overlying defect.¹³ During repair, careful consideration should be given to the rare but dreaded complication of an air embolism. Scalp incisions increase the risk of air embolism due to large, noncollapsible channels with the potential for air entrainment.¹⁴ To minimize this risk, avoid placing patients in a seated position when defects extend to the periosteum, as this lowers hydrostatic pressure within the cerebral veins.¹⁵ Patients should be placed in the recumbent position.

Nails

Skin on the digits has less area and more tension than other body parts, making it paramount to maintain as much healthy tissue as possible and preserve functional anatomy. A common indication for MMS on the nail is nail unit squamous cell carcinoma, which is associated with human papillomavirus (HPV) 16.¹⁶ Removal of the nail plate may or may not be necessary, depending on the accessibility of the tumor. If the tumor damages the matrix, the nail may not grow back normally. Many nail wounds heal well by secondary intention.¹⁷

Case Vignette

A 74-year-old woman presented to the clinic after suspecting 3 warts on her hands. Her past medical history was unremarkable. On exam, she had 2 verrucous papules on the dorsal hands and one on the right fourth lateral nail fold, consistent with verruca. This was confirmed by dermoscopic examination.

These lesions were treated with cryotherapy, and the patient was prescribed a compounded cream of 5-fluorouracil (5FU) and salicylic acid to apply to the wart daily starting 1 week after cryotherapy. The patient followed up with the office every 4 to 6 weeks to receive repeated cryotherapy treatment and continued to apply the 5FU-salicylic acid compound cream at home. After multiple treatments of cryotherapy with no improvement of the lesion on her nail fold, in October 2024, a biopsy was performed, and histology revealed a well-differentiated squamous cell carcinoma. These are most commonly secondary to sun exposure but can also be due to strains of the HPV, specifically HPV 16 in the nail. This strain of the virus is high risk for interference with cell replication and division, which can lead to uncontrolled cell growth and a malignant transformation into squamous cell carcinoma. MMS was performed on the patient in December 2024. The tumor had a preoperative size of 1.2 by 0.7 cm and a postoperative size of 1.6 by 1.2 cm. Due to functional considerations of the nail, the wound was left to heal by secondary intention. After one month, the patient’s nail was healing within normal limits with no signs of recurrence, and the patient reported no pain.

Clinical Insights and Outcomes

MMS relies on careful planning and execution, and reconstruction should emphasize the importance of functional preservation. In addition, proper postoperative care is vital for long-term recovery. Close follow-up is essential to monitor for complications such as infection, hematoma, or wound dehiscence. Silicone gel sheets and corticosteroid ointments effectively minimize hypertrophic scars, while laser therapy can address residual erythema or textural irregularities. High-risk patients, including those with perineural invasion, may require further treatment such as adjuvant radiation.¹⁸ Patient education on sun protection can also influence long-term outcomes. By carefully addressing the unique challenges of each case, Mohs surgeons can optimize outcomes and satisfaction.

Skin Cancer Screenings

Regular skin cancer screenings are vital for the early detection and effective treatment of skin cancer. The American Academy of Dermatology recommends skin cancer screenings at least annually, and monthly self-skin/self-lymph node exams. Screenings every 3 to 6 months may also be recommended after consideration of patient history, family history, level of sun exposure, and other factors.¹⁸ If a suspicious area is detected, a biopsy may be recommended to confirm the diagnosis.

Takeaway

MMS in anatomically complex sites demands surgical precision, reconstructive expertise, and oncologic vigilance. By focusing on careful planning, customized reconstruction, and comprehensive postoperative care, Mohs surgeons can improve both the technical success and quality of life for patients. A patient-centered approach remains at the heart of the process, ensuring that individual needs and concerns are addressed at every step.

Brandon Miller has no financial disclosures and can be reached at bmiller@hdspecialists.com. Miller graduated from the University of Texas at Austin in May 2024 and is a medical assistant for Christopher Downing, MD, FAAD. He is an aspiring medical student and eager to become a dermatologist.

Christopher Downing, MD, FAAD, has no financial disclosures and can be reached at cdowning@hdspecialists.com. Downing is a double board-certified dermatologist and Mohs surgeon. He trained in Texas and Florida and now practices in Houston, Texas, where he treats a variety of skin conditions.

References

1. For patients. American College of Mohs Surgery. Accessed August 18, 2025. www.mohscollege.org. https://www.mohscollege.org/for-patients

2. Siddiqui FS, Leavitt A. Mohs micrographic surgery appropriate use criteria (AUC) guidelines. In: StatPearls. StatPearls Publishing; 2024. Accessed March 28, 2025. https://www.ncbi.nlm.nih.gov/books/NBK603719/

3. Lee DS, Glasgold AI. Correction of nasal valve stenosis with lateral suture suspension. Arch Facial Plast Surg. 2001;3(4):237-240. doi:10.1001/archfaci.3.4.237

4. Dzubow LM. Repair of defects on nasal sebaceous skin. Dermatol Surg. 2005;31(8 pt 2):1053-1054. doi:10.1111/j.1524-4725.2005.31830

5.Repair of small to medium sized nasal defects. Anil Shah MD FACS. Accessed March 14, 2025. https://www.shahfacialplastics.com/articles/repair-small-medium-sized-nasal-defects/

6. Shumrick KA, Campbell A, Becker FF, Papel ID. Modification of the subunit principle for reconstruction of nasal tip and dorsum defects. Arch Facial Plast Surg. 1999;1(1):9-15. doi:10.1001/archfaci.1.1.9

7. Entropion and ectropion repair. Healthdirect Australia. Accessed March 13, 2025. https://www.healthdirect.gov.au/surgery/entropion-and-ectropion-repair

8. Cerejeira D, Bonito F, Goulao J. Periosteal anchoring sutures: a simple method to prevent postoperative ectropion. J Cutan Aesthet Surg. 2020;13(4):368-369. doi:10.4103/JCAS.JCAS_17_20

9. Czyz CN, Cahill KV, Foster JA, Michels KS, Clark CM, Rich NE. Reconstructive options for the medial canthus and eyelids following tumor excision. Saudi J Ophthalmol. 2011;25(1):67-74. doi:10.1016/j.sjopt.2010.10.009

10. Tenzel semicircular flap. American Academy of Ophthalmology. Accessed April 13, 2025. https://www.aao.org/education/image/tenzel-semicircular-flap

11. Sanniec KJ, Carboy JA, Thornton JF. Simplifying lip reconstruction: an algorithmic approach. Semin Plast Surg. 2018;32(2):69-74. doi:10.1055/s-0038-1645882

12. Cherpelis BS, Huang C. Scalp reconstruction procedures. Medscape. Updated September 12, 2023. Accessed March 14, 2025. https://emedicine.medscape.com/article/1828962-overview

13. Halpern M, Adams C, Ratner D. Galeal hinge flaps: a useful technique for immediate repair of scalp defects extending to periosteum. Dermatol Surg. 2009;35(1):127-130. doi:10.1111/j.1524-4725.2008.34391.x

14. Spence NZ, Faloba K, Sonabend AM, Bruce JN, Anastasian ZH. Venous air embolus during scalp incision. J Clin Neurosci. 2016;28:170-171. doi:10.1016/j.jocn.2015.11.019

15. Emamimeybodi M, Hajikarimloo B, Abbasi F, et al. Position-dependent hemodynamic changes in neurosurgery patients: a narrative review. Interdiscip Neurosurg. 2024;36:101886. doi:10.1016/j.inat.2023.101886

16. Bray ER, Tosti A, Morrison BW. Update on squamous cell carcinoma of the nail unit: a human papillomavirus-associated condition. Skin Appendage Disord. 2024;10(3):199-206. doi:10.1159/000537760

17. Gross KG, Steinman HK, Rapini RP. Mohs Surgery: Fundamentals and Techniques. Mosby Incorporated; 1998.

18. Adjuvant therapy: treatment to keep cancer from returning. Mayo Clinic. May 2, 2024. Accessed August 18, 2025. https://www.mayoclinic.org/diseases-conditions/cancer/in-depth/adjuvant-therapy/art-20046687