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 in rare cutaneous tumors: a retrospective study at a Brazilian tertiary university hospital

BackgroundMohs micrographic surgery is an established technique in the treatment of cutaneous neoplasms. It offers higher cure rates and the main indications are non-melanoma malignant skin tumors. Few studies have been performed on the treatment of rare tumors through this technique.ObjectiveTo study rare skin tumors and rare variants of basal cell carcinoma and squamous cell carcinoma submitted to Mohs micrographic surgery in a tertiary service in relation to frequency, disease-free evolution, and applicability of this surgical procedure for this group of tumors.MethodsThis was a retrospective observational study including rare skin tumors and less common variants of basal cell carcinoma and squamous cell carcinoma treated using Mohs micrographic surgery, between October 2008 and April 2021.ResultsDuring the study period, 437 tumors were treated using Mohs micrographic surgery, and 22 (5%) rare skin tumors were selected. The tumors comprised three dermatofibrosarcomas protuberans, two atypical fibroxanthomas, two spiradenomas, two hypercellular fibrohistiocytomas, one primary cutaneous adenocarcinoma, one trichoblastoma, one porocarcinoma, one chondroid syringoma, one cutaneous angiosarcoma, one Merkel cell carcinoma, and one sebaceous carcinoma. Six other cases of rare basal cell carcinoma variants with trichoepitheliomatous differentiation, metatypical basal cell carcinoma, and clear cell squamous cell carcinoma were included. There were no cases of recurrence after an average of six years of follow-up.Study limitationsThis is a retrospective study on rare neoplasms carried out in a single referral center, and this surgical technique isn’t widely available in the public service.ConclusionThis retrospective case series showed that Mohs micrographic surgery is an appropriate treatment for rare skin tumors. They corresponded to 5% of the tumors treated by the technique during a 12-year-period, with no recurrences identified.     

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.     

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.     

Surgical Tip: The Double-Bladed Scalpel in Mohs Micrographic Surgery

Mohs micrographic surgery is applied as the primary method of treatment for various cutaneous neoplasms. Many other methods that are modified applications of Mohs micrographic surgery have also been suggested. We introduce a technique, which is a modified vertical method of Mohs micrographic surgery using the double-bladed scalpel.     

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.     

Management of unusual cutaneous malignancies: atypical fibroxanthoma, malignant fibrous histiocytoma, sebaceous carcinoma, extramammary Paget disease

Atypical fibroxanthoma, malignant fibrous histiocytoma, sebaceous carcinoma, and extramammary Paget disease are rare cutaneous tumors. Their recognition and diagnosis are critical in decreasing long-term morbidity and mortality. Surgical excision is the treatment of choice for these tumors, and Mohs micrographic surgery has been shown to be as favorable or better than wide local excision in providing long-term clearance rates.     

Mikrographisch kontrollierte Chirurgie (3D‐Histologie) beim Melanom

Frederic E. Mohs was the first to apply micrographic surgery in cutaneous surgery. As a result in the English literature, micrographic surgery (3D‐histology) is usually called Mohs micrographic surgery (MMS). Techniques of 3D‐histology have been applied in various skin tumours. The method is most suitable for tumours with continuous spread. Excisions with 3D‐histology can be performed with smaller initial safety margins. Thus less normal tissue is excised and often better cosmetic results can be obtained. Techniques of 3D‐histology such as the Mohs technique (MMS) and the “Tuebingen Cake” technique are compared with routine histopathology. In addition, the current status of 3D‐histology in cutaneous melanoma is assessed. Prospective randomized studies on 3D‐histology in cutaneous melanoma are not available. Nevertheless, 3D‐histology should usually be employed for lentigo maligna melanoma. In functionally and cosmetically important areas (face, hand, foot) 3D‐histology may allow reduced safety margins in other histological types of cutaneous melanoma.     

Mohs micrographic surgery for thin stage I malignant melanoma: rationale for a modern management strategy.

Mohs micrographic surgery is presented as a rational surgical management approach for thin malignant melanoma. Advantages of the Mohs micrographic surgery fresh-tissue technique include tissue conservation, low local recurrence rates, and outpatient reconstruction. It is likely that in the future many physicians and patients will choose Mohs micrographic surgery for the surgical treatment of thin malignant melanoma.     

Mohs surgery. Technique, indications, applications, and the future

Each year, it is estimated, more than 500,000 new cases of nonmelanoma skin cancer develop. The majority of these cutaneous neoplasms are treated by various modalities that include excision, electrodesiccation and curettage, cryosurgery, and irradiation, with greater than 90% success. Certain of the remaining primary tumors, as well as recurrent carcinomas, present a demanding therapeutic challenge. For these lesions, Mohs surgery has evolved as the most reliable and cost-effective treatment modality, offering maximal preservation of normal tissue and therefore the lowest functional and cosmetic morbidity. In this review, the history and evolution of Mohs surgery and the technique itself will be briefly outlined. The indications for Mohs surgery, together with methods of handling the postoperative wound and future applications of the technique, will be discussed in detail.     

Microcystic adnexal carcinoma: forty-eight cases, their treatment, and their outcome

BACKGROUND: Microcystic adnexal carcinoma, or sclerosing sweat duct carcinoma, is an uncommon cutaneous neoplasm associated with extensive local invasion. The standard of care with regard to the best excisional method in treating microcystic adnexal carcinoma has not been established. OBJECTIVES: To perform a retrospective study comparing patients treated by Mohs micrographic surgery with those treated by wide excision and to elucidate the epidemiological features of microcystic adnexal carcinoma. PATIENTS AND METHODS: A retrospective analysis of a case series involving 48 primary and referral patients diagnosed as having microcystic adnexal carcinoma using standardized criteria. All cases were reviewed by the same dermatopathologists. RESULTS: Microcystic adnexal carcinoma predominantly affects the left side of the face of middle-aged women. Microcystic adnexal carcinoma is misdiagnosed 30% of the time. The recurrence rate is 1.98% per patient-year. Mohs micrographic surgery and simple excision show comparable complication rates. Clear margins were obtained in fewer procedures and, therefore, fewer office visits when the lesions were treated with micrographic surgery. The defect surface area after full extirpation following Mohs micrographic surgery was a mean of 4 times that of the clinically apparent size. The wide range of difference between the pre- and the post-Mohs micrographic surgery surface area noted in our data indicates that a margin cannot be safely predicted. CONCLUSIONS: Microcystic adnexal carcinoma is a predominantly left-sided, locally aggressive facial tumor, which results in significant morbidity. Our data do not support the use of standardized predictable margins. Mohs micrographic surgery is a reasonable initial treatment, as it accomplishes cure in fewer office visits and does not rely on predicted margins.     

A systematic review of treatment modalities for primary basal cell carcinomas.

OBJECTIVE: To systematically review the literature for studies reporting on recurrence rates of basal cell carcinomas (BCCs) after different therapies. DESIGN: We reviewed all studies published in English, French, German, Dutch, Spanish, or Italian between 1970 and 1997 that prospectively examined recurrence rates for at least 50 patients with primary BCCs observed for at least 5 years after treatment with Mohs micrographic surgery, surgical excision, curettage and electrodesiccation, cryosurgery, radiotherapy, immunotherapy with interferon or fluorouracil, or photodynamic therapy. SETTING: Department of Dermatology, University Hospital Maastricht, Maastricht, the reference center for dermatologic oncology and Mohs micrographic surgery in the Netherlands. MAIN OUTCOME MEASURES: The recurrence rates after different therapies for BCCs, resulting in the development of guidelines for the treatment of these disorders. RESULTS: Of 298 studies found in several electronic databases, only 18 met the requirements and could be used for analysis. Tumors treated with Mohs micrographic surgery show the lowest recurrence rates after 5 years, followed in order by those treated with surgical excision, cryosurgery, and curettage and electrodesiccation. CONCLUSIONS: Recurrence rates for different therapies could not be compared because of a lack of uniformity in the method of reporting, so evidence-based guidelines could not be developed. We surmise that Mohs micrographic surgery should be used mainly for larger, morphea-type BCCs located in danger zones. For smaller BCCs of the nodular and superficial types, surgical excision remains the first treatment of choice. Other treatment modalities can be used in patients in whom surgery is contraindicated. Immunotherapy and photodynamic therapy are still investigative.     

Multidisciplinary approach to large cutaneous tumors of the head and neck

Large cutaneous tumors of the head and neck provide challenges for complete excision and optimal reconstruction. Collaborative intraoperative Mohs micrographic surgery offers efficient and reliable extirpation of large cutaneous malignancies of the head and neck and immediate reconstruction of resultant defects.     

Second intention healing after Mohs micrographic surgery

BACKGROUND: Although second intention healing has been used for many years in Mohs micrographic surgery, it has lost popularity. This is due to the long process and functional alteration of important anatomical units if certain wound healing factors are not carefully taken into consideration. OBJECTIVE: To review indications, contraindications, complications, advantages, disadvantages, as well as basic concepts of the wound healing process, wound care and antibiotic prophylaxis in the management of open wounds after Mohs surgery. METHODS: A short but comprehensive review of studies published in the literature dealing with second intention healing as a reconstruction alternative option in certain situations. CONCLUSIONS: Second intention healing is a simple and cost-effective method for reconstruction after Mohs micrographic surgery in well-defined cases. It allows adequate tumoral control with good to excellent functional and cosmetic results.     

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。     

影像学检查在辅助确定皮肤肿瘤手术切缘中的应用进展

目前对于皮肤肿瘤的治疗仍首选手术切除,手术中在尽量做到切净肿瘤的同时,最大限度的保留正常皮肤,因此对准确界定肿瘤边缘提出了更高的要求.尽管Mohs显微描记手术可以准确界定肿瘤边缘,但Mohs显微描记手术因其耗时多,费用高,过程繁琐等缺点限制了在临床的推广.近年来荧光染色、皮肤CT以及皮肤镜等影像学检查的快速发展,恰好解决了这一难题.研究证实,这些影像学检查在皮肤肿瘤切除术中可以起到辅助确定肿瘤边缘的作用,临床上有助于确定术前及术中肿瘤边界,最终使得手术结果可以同时达到治疗和美观的要求.尤其是皮肤镜、光动力荧光染色和皮肤CT技术相比于Mohs显微描记手术有着创伤小、操作简单、费用低等优点,因此在临床上更容易普及,具有广泛的应用前景.     

Rapid HMB-45 staining in Mohs micrographic surgery for melanoma in situ and invasive melanoma

BACKGROUND: Accurate interpretation of frozen sections in the treatment of melanoma by Mohs micrographic surgery may be difficult. OBJECTIVE: Our purpose was to review the literature on the role of Mohs micrographic surgery in the treatment of melanoma and to demonstrate the added benefits of using rapid HMB-45 staining in Mohs micrographic surgery for the treatment of melanoma. METHODS: Twenty cases of melanoma were included in our study. Histologic diagnosis in each case was made by means of excisional biopsy specimens and permanent sections. Mohs micrographic surgery was performed with 3-mm margins used for each stage. Each Mohs frozen section was stained with HMB-45. In addition, routine frozen sections stained with hematoxylin-eosin were also prepared for comparison. All tissues were also sent for permanent sections. These permanent sections were cut similarly to Mohs-oriented sections because they were sectioned horizontally. Since they were serving as the standard, no staining with HMB-45 was performed on these permanent sections. Further stages with 3-mm margins were taken until tissues stained negative. Frozen sections were compared with permanent sections at each stage of resection. RESULTS: Eleven of the 20 cases stained positive with HMB-45 antibody on the first Mohs stage. These results were consistent with findings on permanent sections. Ten of the 11 cases were cleared by the first stage. One of the 11 cases required 3 stages because margins were not cleared and the specimens stained HMB-45 positive. However, permanent sections in this case revealed no tumor in the second stage. Nine of 20 cases did not stain with HMB-45 on the first layer of Mohs excision. This was consistent with findings on permanent sections. CONCLUSION: HMB-45 staining serves as a rapid technique to aid in the interpretation of frozen sections during Mohs micrographic surgery in the treatment of melanoma.     

A Case of Trichilemmal Carcinoma Treated with Mohs Micrographic Surgery

Trichilemmal carcinoma is a cutaneous adnexal tumor originating from the outer root sheath of hair follicle, and it was first described by Headington in 1976. Clinically, it usually occurs as an asymptomatic solitary papule, nodule or mass on the face or scalp. This neoplasm is a malignant counterpart of trichilemmoma, and it has been reported in the literature as trichilemmal carcinoma, tricholemmal carcinoma, malignant trichilemmoma, and tricholemmocarcinoma. Although histologically, trichilemmal carcinoma frequently has maliganant features, it has a relatively benign clinical behavior. We think Mohs micrographic surgery is a useful treatment modality in trichilemmal carcinoma because the final skin defect is smaller than a wide excision. We report a case of primary trichilemmal carcinoma which had developed on the face, treated with Mohs micrographic surgery.     

Cancer of the forehead and temple regions

Several characteristics inherent in tumors of the forehead and temple provide therapeutic challenges for the physician. These include spread along anatomic structures, a propensity toward aggressive growth patterns, the risk of nerve damage, and the preservation of important cosmetic landmarks. As a result of these problems, Mohs micrographic surgery is often indicated in the treatment of skin cancer of the forehead and temple. The high cure rates afforded by micrographic surgery, even for aggressive tumors, and tissue conservation are benefits to the patient. Although most BCCs and SCCs in this region can be handled by a dermatologic surgeon, patients may present with aggressive or neglected tumors exhibiting extensive invasion. These patients may require a cooperative approach between the dermatologic and head and neck surgeon to achieve complete tumor extirpation or appropriate reconstruction. In this article, we have tried to indicate the rationale behind the use of Mohs micrographic surgery for tumors of the forehead and temple. In selected tumors, a team approach between the micrographic and other surgeons will maximize both tumor excision and functional and cosmetic repair for the patient.     

Mohs micrographic surgery: Facts and controversies

The field of Mohs micrographic surgery has expanded in the last 70 years, as have the indications for the procedure and the techniques that have been used. As a result, differences in the practice of Mohs micrographic surgery have emerged. This contribution explores current controversies within Mohs micrographic surgery and critically appraises the available evidence on both sides of the issues.