Mohs micrographic surgery: a review of indications,technique, outcomes,and considerations

Mohs micrographic surgery is a specialized form of skin cancer surgery that has the highest cure rates for several cutaneous malignancies. Certain skin cancers can have small extensions or “roots” that may be missed if an excised tumor is serially cross-sectioned in a “bread-loaf” fashion, commonly performed on excision specimens. The method of Mohs micrographic surgery is unique in that the dermatologist (Mohs surgeon) acts as both surgeon and pathologist, from the preoperative considerations until the reconstruction. Since Dr. Mohs’s initial work in the 1930s, the practice of Mohs micrographic surgery has become increasingly widespread among the dermatologic surgery community worldwide and is considered the treatment of choice for many common and uncommon cutaneous neoplasms. Mohs micrographic surgery spares the maximal amount of normal tissue and is a safe procedure with very few complications, most of them managed by Mohs surgeons in their offices. Mohs micrographic surgery is the standard of care for high risks basal cell carcinomas and cutaneous squamous cell carcinoma and is commonly and increasingly used for melanoma and other rare tumors with superior cure rates. This review better familiarizes the dermatologists with the technique, explains the difference between Mohs micrographic surgery and wide local excision, and discusses its main indications.     

Mohs micrographic surgery. Fresh-tissue technique

Because of its superior histologic control, when compared with conventional surgery, Mohs micrographic surgery offers 5-year cure rates of 98 to 99% when dealing with aggressive, extensive, and/or recurrent cutaneous neoplasms. Because the fresh-tissue technique is faster, less painful, and more tissue conserving, allows for immediate repairs, yields higher quality histologic preparations, and facilitates an interdisciplinary approach, it has become the preferred method of performing Mohs micrographic surgery. The fixed-tissue technique does offer certain advantages when dealing with (1) vascular neoplasms or tumors in vascular areas; (2) tumor in deep, narrow spaces; (3) tumor invading bone; or (4) tumors capable of implantation and metastatic spread. However, a modification of the fresh-tissue technique, the use of the CO2 laser, or an interdisciplinary approach may also allow the Mohs surgeon to effectively deal with these problem cases.     

Dermatofibrosarcoma protuberans (DFSP) in children: A combined multidisciplinary approach

Dermatofibrosarcoma protuberans (DFSP) is rare, comprising (1%‐6%) of all sarcomas. The incidence is less than one per million before the age of 20. It is a locally aggressive tumor with a low risk of metastasis. We share our experience in the management of three pediatric patients with complex cases of DFSP in a combined surgical approach involving plastic and dermatologic surgery, using the slow Mohs micrographic surgery technique.     

Repair of nasal tip and alar defects using cheek-based 2-stage flaps: an alternative to the median forehead flap

OBJECTIVE: To describe our use of cheek-based 2-stage transposition flaps for repairing Mohs surgery defects of the lower third of the nose. DESIGN: Retrospective case series. SETTING: Private dermatologic day surgery facility.Patients Twenty-eight patients with defects of the lower third of the nose after Mohs surgery.Intervention Ten alar and 18 nasal tip defects repaired using cheek-based 2-stage transposition flaps. MAIN OUTCOME MEASURES: Acceptability of procedure to patient, complications, and appearance from photographic records. RESULTS: The procedures were well tolerated and achieved good cosmetic results without major complications. CONCLUSIONS: These flaps allow repair of extensive defects of the nasal tip and ala with the patient under local anesthesia. This approach provides an alternative to the median forehead flap for nasal tip repairs.     

Special stains in Mohs surgery

The excellent cure rates associated with Mohs micrographic surgery depend on accurate interpretation of complete and high-quality microscopic frozen sections. Reliable interpretation of microscopic slides is only possible if the surgeon can distinguish tumor cells from surrounding normal tissue. By highlighting tumor cells with a chromogen that is visible on light microscopy, immunostaining allows the Mohs surgeon to distinguish tumor from normal cells in these challenging scenarios. This article focuses on practical aspects involving the most commonly used immunostains in dermatologic surgery, including MART-1 for melanocytic neoplasms, cytokeratin stains for keratinocytic neoplasms, and CD34 stains for dermatofibrosarcoma protuberans.     

Combined sentinel lymphadenectomy and mohs micrographic surgery for high-risk cutaneous squamous cell carcinoma

BACKGROUND: There are subgroups of cutaneous squamous cell carcinoma (SCC) that have a higher risk for both regional and distant metastasis. When cutaneous SCC does metastasize, it typically spreads first to local nodal groups. Sentinel lymph node (SLN) localization has been successfully used to evaluate nodal metastasis in breast carcinoma, melanoma, and other select tumors. It may also be useful in certain high-risk cutaneous SCCs. Currently, Mohs micrographic surgery is the treatment of choice for these tumors. METHODS: A patient presented with a high-risk recurrent SCC on the forehead. The regional nodal groups were clinically negative and radiographically negative by computed tomographic scan. Sentinel lymphadenectomy was performed by means of technetium 99m-radiolabeled sulfur colloid. The main tumor was resected with Mohs micrographic surgery. RESULTS: A left preauricular SLN was localized by lymphoscintigraphy. The SLN was located intraoperatively by means of a gamma probe and excised. Subsequent pathologic evaluation of the SLN was negative for evidence of metastatic SCC by light microscopy with hematoxylin and eosin, and with immunohistochemical stains for cytokeratins AE1 and AE3. The day after SLN excision, the tumor was removed via Mohs micrographic surgery with clear surgical margins after a total of 8 stages. Aggressive subclinical spread by both subcutaneous "skating" and perineural invasion was noted. CONCLUSION: The combination of Mohs micrographic surgery and sentinel lymphadenectomy is feasible and has theoretical utility in the management of a subset of cutaneous SCCs at high risk for metastasis. The ability of sentinel lymphadenectomy to identify regionally metastatic cutaneous SCC as well as the additive benefit of SLN and Mohs micrographic extirpation in the treatment of high-risk cutaneous SCC remain to be further clarified.     

Predictors of extensive subclinical spread in nonmelanoma skin cancer treated with Mohs micrographic surgery

BACKGROUND: In nonmelanoma skin cancer, the clinically visible portion may represent a small fraction of microscopic tumor spread. Previous studies have examined individual risk factors for subclinical spread based on patient and tumor characteristics. However, these risk factors have not been prioritized or studied in combination. OBJECTIVE: To identify the most predictive risk factors for extensive subclinical tumor spread. DESIGN: Retrospective analysis of 1131 Mohs micrographic surgical cases. Variables analyzed included patient age, sex, and immune status and lesion size, location, histologic subtype, and recurrence. Logistic regression was applied to identify important combinations of tumor characteristics and to quantify relative odds of spread. SETTING: Academic referral center. PATIENTS: Consecutive sample of all referred patients treated by a single Mohs micrographic surgeon in a 3-year period. MAIN OUTCOME MEASURE: Number of Mohs micrographic surgical layers required to clear a tumor, with 3 or more layers defined as extensive subclinical spread. RESULTS: The highest-risk tumors, with odds ratios greater than 6.0, were basosquamous and morpheaform basal cell carcinoma (BCC) on the nose, morpheaform BCC on the cheek, and those with a preoperative size greater than 25 mm. Other important risk factors were recurrent and nodular BCC on the nose; location on the eyelid, temple, or ear helix; neck tumors and recurrent BCC in men; and tumor size greater than 10 mm. Patients younger than 35 years were at lower risk. Increasing age and immunocompromise were not significant predictors. CONCLUSION: Identification of lesions likely to exhibit extensive subclinical spread can help guide management to ensure complete tumor eradication and thereby reduce the risk of recurrence and its associated morbidity and cost.     

Large facial basal cell carcinoma treated with multimodal combination therapy

Large basal cell carcinomas (BCCs) with mixed intratumoral histology can present treatment challenges. Although a single treatment modality may be appropriate for some portions of the tumor, it may prove to be inadequate or overly aggressive for others. We describe a patient with a large facial BCC who was referred to our clinic for Mohs micrographic surgery. Biopsies revealed both noduloinfiltrative and superficial patterns. To excise the tumor completely would have been disfiguring, and topical therapy alone would have been inadequate. A multimodal approach using Mohs micrographic surgery to excise the central nodular portion and topical imiquimod to treat the surrounding superficial portion resulted in an excellent clinical outcome. This approach, which minimizes morbidity by capitalizing on the benefits of various techniques, can be applied to any BCC demonstrating distinct nodular and superficial portions.     

Adenocarcinoma of mammary-like glands of the vulva: Report of a case and review of the literature

Mammary-like glands are a poorly recognized structure of normal vulvar skin. Adenocarcinomas arising from these glands are rare and represent a distinct clinicopathologic entity that must be distinguished from metastatic tumors. We reviewed 19 cases reported in the literature and describe a 51-year-old patient with a long-standing nodule on her right interlabial sulcus. Excisional biopsy and Mohs micrographic surgery demonstrated an infiltrating adenocarcinoma of the mammary-like glands involving the dermis and subcutis. On review of all 20 cases, the mean age at diagnosis was 59.6 years, the labia majora were involved in 13 cases (65%), and the mean lesional size was 2.5 cm. The tumor's histologic patterns varied greatly, although the histomorphologic similarity among this neoplasm, sweat gland carcinomas, and invasive extramammary Paget disease suggested a morphologic spectrum among these tumors. Criteria for establishing the diagnosis of adenocarcinoma of mammary-like glands include identifying transition zones between normal mammary-like glands and adenocarcinomatous areas. This tumor is best categorized as a locally aggressive neoplasm with a low risk for widespread metastasis. Use of aggressive surgical therapeutic regimens, particularly in the case of tumors localized to the skin, must be reassessed, especially given the likelihood of long-term morbidity with such regimens. In our patient, successful Mohs micrographic surgery suggests that alternate management may be adopted for tumors localized to the skin, especially in elderly patients.     

Carcinoma anexial microquístico: la cirugía micrográfica de Mohs como tratamiento de elección

Introduction and objectivesMicrocystic adnexal carcinoma is a rare and aggressive tumor that manifests clinically as a subcutaneous nodule located on the head or neck. The tumor can be confused clinically and histologically with other benign and malignant skin lesions, often leading to inappropriate initial treatment. The chief concern with microcystic adnexal carcinoma is the elevated morbidity and the high rate of recurrence after wide local excision. Recent preliminary studies point to higher cure rates with Mohs micrographic surgery.Material and methodsWe reviewed the medical histories of 6 consecutive patients with microcystic adnexal carcinoma who underwent Mohs micrographic surgery in our dermatology department between 1995 and 2007.ResultsIn all cases, lesions were located on the head and were primary tumors. Seventy percent of the tumors were wrongly diagnosed initially as basal cell carcinoma. Perineural invasion was not detected in any patient, and all were free of recurrence after between 1 and 12 years of postoperative follow-up.ConclusionsThe absence of perineural involvement and substantial cell atypia can be attributed to the lesions being primary tumors. This would provide a rationale for definitive radical treatment of the primary tumor from the outset to avoid the complications associated with recurrence. The site and the absence of recurrence in all our patients who underwent Mohs micrographic surgery support the use of this technique as the treatment of choice in microcystic adnexal carcinoma.     

Nephrogenic Fibrosing Dermopathy

Mammary‐like glands are a poorly recognized structure of the normal vulvar skin. Adenocarcinomas occur rarely in these glands and represent a distinct clinicopathologic entity that must be distinguished from metastatic tumors. We present a case of a 51‐year‐old patient with a long‐standing nodule on her right labium majus. Excision with subsequent Mohs micrographic surgery revealed an infiltrating adenocarcinoma of the mammary‐like glands involving the dermis and subcutis. We review all cases thus far reported (including the case presented herein) and identify important clinical and morphologic features of this tumor. A significant histopathological and immunohistochemical overlap between this neoplasm, sweat gland carcinomas, and invasive extramammary Paget's disease was recognized; suggesting the existence of a morphologic spectrum between these entities. Criteria for establishing the diagnosis of adenocarcinoma of mammary‐like glands are reviewed, including the importance of identifying transition zones between normal mammary‐like glands and malignant glands. We believe that this tumor is best categorized as a locally aggressive neoplasm with a low metastatic potential and death from disease is uncommon. The successful treatment of this case by Mohs micrographic surgery suggests that an alternate management approach may be adopted for these tumors, particularly in elderly patients.     

Mohs显微外科手术75例回顾分析

目的 分析Mohs显微外科手术的意义及特点.方法 对75例Mohs显微外科手术病例进行回顾性分析.结果 手术病例中多为老年人,基底细胞癌、Bowen病等为最常见的受治病种.部分肿瘤经多次扩大切除才被切净,最终切除面积大于常规方法切除的面积.68%为头面部手术,头面部缺损多需要应用复杂成形修复.手术缺损最终大小与患者年龄及皮肤肿瘤发生部位无关.结论 对于切除皮肤肿瘤,Mohs显微外科手术比常规切除方法更彻底,有助于切除后手术缺损的成形修复.     

Mohs显微描记手术治疗皮肤恶性肿瘤56例临床分析

目的探讨Mohs显微外科手术治疗皮肤恶性肿瘤的临床效果。方法对56例皮肤恶性肿瘤沿皮损周围行扩大切除术,将切除的边缘组织染色,按Mohs显微描记手术法冰冻切片,观察残余肿瘤细胞情况。结果 56例患者随访1～5年,其中53例患者伤口愈合良好,美容效果佳,无复发现象,56例中仅复发3例。结论 Mohs显微外科手术治疗皮肤恶性肿瘤具有损伤小、美容效果好、复发率低和安全性好的优点。     

Mohs micrographic surgery for cutaneous malignancies: A focus review of its indications in pediatric age groups

Mohs micrographic surgery (MMS) is a highly specialized technique that has been successful in the treatment of a variety of skin tumors. The technique can be performed as an outpatient procedure and encompasses surgical excision and intraoperative assessment of tumor margins in one setting by the same physician. The process ensures precise margin control with maximal preservation of healthy tissues. Mohs micrographic surgery has been practiced worldwide, including in the United States, Europe (United Kingdom, Germany, Spain, Netherlands, Switzerland), and Australia. Although it is commonly performed in adults with greater success, it has been discussed less frequently in children. In this article, we describe several cutaneous tumors in children and the role of Mohs micrographic surgery in their management. A PubMed search was conducted to review the most common cutaneous tumors in children treated using Mohs micrographic surgery. In this review, we discuss indications for Mohs micrographic surgery and pertinent studies examining success rates in children. Mohs micrographic surgery has been used to treat several tumors in children and offers the advantage of high cure rates and tissue conservation. This report emphasizes the benefits of Mohs micrographic surgery in children and highlights several cutaneous tumors for which it has been used to treat successfully.     

周围组织的 Mohs 显微描记外科手术治疗乳房外 Paget 病

目的：探讨周围组织的 Mohs 显微描记外科手术治疗乳房外 Paget 病（EMPD）的有效性。方法对28例 EMPD 患者术前肿瘤侵犯的深度和范围进行判断,术前1 d 外敷20%盐酸氨酮戊酸,伍德灯下观察并标记手术切缘。切取荧光定位后的边缘皮肤组织,按 Mohs 显微描记外科技术方法仅对周围组织进行冰冻切片检查,同时进行肿瘤切除。术后3～6个月随访1次,观察局部复发和转移情况。结果28例患者中,男25例,女3例。6例患者需要3次冰冻切片,12例患者要2次冰冻切片,平均1.86次。随访5～72个月,局部复发者3例,1例尿毒症患者随访2年因肝转移死亡。结论周围组织的 Mohs 显微描记外科手术是一省时和有效的治疗EMPD 的方法。     

改良Mohs显微描记手术治疗Merkel细胞癌二例

【摘要】 Mohs显微描记手术是切除皮肤肿瘤的理想术式。本文2例Merkel细胞癌患者行改良Mohs显微描记手术切除肿瘤，随访1年余，肿瘤未复发。与传统扩大切除术相比，改良Mohs手术是Merkel 细胞癌患者更好的选择。     

Mohs moat: Peripheral cutaneous margin clearance in a collaborative approach for aggressive and deeply invasive basal cell carcinoma

Although Mohs micrographic surgery is the standard of care for large, aggressive or recurrent non‐melanoma skin cancers of the head and neck, tumours that involve deep underlying structures (including bone, parotid gland and named nerves) are impractical for extirpation under local anaesthesia. Such cases are often referred to a head and neck surgeon, who typically relies on intraoperative frozen section analysis of the peripheral cutaneous margin. Here we describe the use of the Mohs moat technique as part of a collaborative approach for the treatment of aggressive and deeply invasive basal cell carcinoma that allows an analysis of the complete peripheral cutaneous margin and results in decreased operating room and general anaesthesia time.     

Mohs surgery in Australia: a survey of work practices

Background: Mohs micrographic surgery is the preferred treatment for certain skin cancers. It had already been considerably refined prior to its introduction into Australia in 1978, refinement has continued since. Documenting the work practices of Australian Mohs surgeons serves to clarify the current role of Mohs surgery and may help tailor future Mohs fellowship programs. Methods: A survey was conducted to investigate the characteristics and clinical practices of Australian Mohs surgeons, particularly as they relate to skin cancer management and aesthetic dermatology. Results: The typical Australian Mohs surgeon is male (90%), works in a group private practice (70%), and is aged 40–44 years (37%). Mohs surgery is generally reserved for tumours that are located on the head, neck, digits or genitals (98%), and flap reconstructions are the commonest repair types performed (48%). Laser and cosmetic injectable treatments form part of many Mohs surgeon's repertoires. Conclusion: Australian Mohs surgeons make an important contribution to the management of skin cancer in Australia and many are skilled in laser and cosmetic procedures. The increasing number of cases performed annually and the familiarity with laser and cosmetic therapies reinforces Australian dermatologists as leaders in these important areas of dermatology.     

Mohs micrographic surgery pearls

Mohs micrographic surgery has evolved over the last 60 years from fixed-tissue chemosurgery with secondary intention healing to fresh-tissue surgical excision utilizing advanced histotechnology and reconstructive techniques. This evolution has occurred while preserving the fundamental characteristics of Mohs surgery: microscopically controlled tumor excision by one surgeon acting as pathologists to ensure complete tumor extirpation while maximally conserving tissue. Refinements, modifications, and clinical pearls will be outlined that uphold these tenets and enhance the quality of patient care.