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.     

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.     

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.     

Special considerations for Mohs micrographic surgery on the eyelids, lips, genitalia, and nail unit

Although skin cancers on the eyelids, lips, genitalia, and the nail unit are infrequent, some skin cancers can have higher recurrence rates in these anatomic locations. Intrinsic to Mohs micrographic surgery (MMS) is maximal tissue preservation and high cure rates, making it a worthwhile procedure for these sensitive anatomic areas to ameliorate any functional or aesthetic compromise. The Mohs surgeon can provide a great service to patients by being aware of the anatomy, specialized instruments, unique histology, and potential complications when performing MMS on these areas.     

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.     

Treatment options in melanoma in situ: topical and radiation therapy,excision and Mohs surgery

Background The treatment of melanoma in situ (MIS), particularly the lentigo maligna (LM) subtype, has been a controversial subject in the literature for over a decade. Surgical excision with 5 mm margins is the standard of care in the USA, while several variations of Mohs surgery are frequently used to treat clinically ill‐defined lesions. Radiation is much less frequently used. Topical imiquimod has also been more recently proposed, in small case reports in the literature, as a therapy for MIS. However, controversies exist with all approaches. Objective To review the current literature regarding topical imiquimod, radiation therapy, surgical excision, and the various forms of Mohs surgery for MIS, focusing on the LM subtype. Methods A literature search was performed in the PubMed database using the following terms: “melanoma in situ,”“lentigo maligna,”“excisional surgery,”“Mohs micrographic surgery,”“radiation therapy,” and “imiquimod.” Articles relevant to the treatment of MIS were reviewed and reported herein. Results Studies of imiquimod therapy for MIS are hampered by small study numbers and short follow‐up periods. The few, better‐designed studies reveal relatively low cure rates. In addition, literature review reveals that a significant percentage of cases of MIS that are initially diagnosed as in situ disease by biopsy subsequently prove to have an invasive component upon complete excision. This finding suggests that topical therapy of any kind may be problematic. Studies of radiation therapy for MIS have relatively small numbers of patients and short follow‐up. Multiple studies of excisional surgery have shown that 5 mm margins are often insufficient to clear the LM subtype of MIS due to unseen subclinical extension, accounting for this treatment’s reported 8–20% recurrence rate. Finally, a number of variants of traditional frozen section Mohs surgery have been utilized to try and achieve complete peripheral margin assessment of clinically ill‐defined LM lesions. All studies are retrospective, and most are single‐institution and frequently single‐operator, limiting the meaningfulness of their results. Nevertheless, they involve moderate numbers of patients, and many have at least a five year follow‐up. Collectively, they suggest recurrence rates in the range of 0.5–3.0%. Conclusion Topical imiquimod therapy appears to provide relatively low cure rates for MIS, and because some of these lesions contain an unrecognized invasive component, should be used with extreme caution to treat this disease. Radiation therapy may be a useful second‐line therapy if surgery is contraindicated. Excisional surgery is an appropriate therapy for clinically well‐defined MIS; however, margins larger than 5 mm may be required when treating larger or indistinct lesions. Finally, for clinically ill‐defined LM arising on sun‐damaged skin, especially in regions of aesthetic concern, some form of complete peripheral margin assessment – one of the various forms of Mohs surgery – may provide the highest cure rate and create the smallest surgical defect.     

Squamous cell carcinoma of the skin: epidemiology,classification, management,and novel trends

Squamous cell carcinoma (SCC) is the second most common non‐melanoma skin cancer. It originates from epidermal keratinocytes or adnexal structures (such as eccrine glands or pilosebaceous units). We describe the salient features of cutaneous SCC. We also review novel classification schemes proposed during the last decade which attempt to stratify SCC lesions based on prognosis. Biopsy leads to definitive diagnosis. Treatment includes surgical excision; Mohs micrographic surgery produces excellent cure rates and spares the maximal amount of tissue. Other modalities include electrodessication and curettage, cryosurgery, radiotherapy, topical medications, photodynamic therapy, and systemic therapy. Management and follow‐up depend on the risk stratification of individual lesions.     

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.     

MOHS micrographic surgery for head and neck nonmelanoma skin cancer: An approach for ENT surgeons

Surgery is the main approach for skin cancer, with Mohs micrographic surgery (MMS) allowing the highest cure rates, best esthetics and superior functional outcomes. Ear, nose, and throat (ENT) surgeons are often challenged with patients presenting skin cancer, needing appropriate expertise to its adequate management. This paper highlights the most important aspects of MMS, enabling ENT surgeons to become familiar with its fundamental aspects. A review of the literature was performed, concomitantly presenting the author's outcomes as an ENT surgeon. A total of 51 MMSs were performed in 41 patients, and 78.4% of the tumors were cutaneous basal cell carcinomas (cBCCs), 19.6% were cutaneous squamous cell carcinomas (cSCCs), and one case was a microcystic adnexal carcinoma. Most tumors were located in high‐risk areas (88.2%), and 84.3% of them were ≥10 mm in diameter. Most tumors (90.2%) required no more than two MMS excision steps to be completely removed. All cases were managed by reconstruction either using flaps or grafts. Recurrence occurred in only 2% of the cases. This study addressed the main issues of MMS, which may be important in ENT surgeons' daily practice.     

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.     

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。     

5-year recurrence rates of Mohs micrographic surgery for aggressive and recurrent facial basal cell carcinoma

Mohs micrographic surgery allows for complete microscopic examination of the surgical margin when treating aggressive and recurrent facial basal cell carcinomas. This leads to the highest cure rates and maximal preservation of healthy tissue. The 5-year recurrence rates of 587 aggressive and/or recurrent facial basal cell carcinomas treated during 1993 to 2003 at our centre were studied retrospectively. The resulting 5-year recurrence rates using Kaplan-Meier survival analysis were 2.1% for primary (previously untreated) tumours, 5.2% for recurrent basal cell carcinomas and 3.3% overall. In total, 87.9% of the tumours required at least two stages of Mohs micrographic surgery. The surgical defect's size after complete excision was, on average, approximately twice the size of the defect after excision of the clinically visible tumour with a 2-3 mm margin. Mohs micro-graphic surgery is underused in Scandinavia despite being the treatment of choice for aggressive and recurrent facial basal cell carcinomas.     

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.     

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.     

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 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.     

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.     

Recurrent and metastatic primary cutaneous mucinous carcinoma after excision and Mohs micrographic surgery

Primary cutaneous mucinous carcinoma is a neoplasm of sweat gland origin. Optimal management guidelines have not been established for this rare tumor. It is treated most commonly by traditional excision and more recently by Mohs micrographic surgery in an effort to decrease its recurrence rate. We report a case of primary cutaneous mucinous carcinoma with multiple recurrences and metastases following 3 excisions and 2 Mohs procedures, highlighting the potential difficulty in treating this cancer and suggesting the need for a more effective treatment approach.     

改良Mohs显微描记手术26例分析

目的　观察改良Mohs显微描记手术治疗皮肤癌的临床疗效。方法　沿皮损外约2mm～4mm切除病灶,用数码相机拍下切除组织的位置及形状,并即时打印,将送检的组织在打印图纸上及病人身上相对应的位置作相同的记号。然后按Mohs显微描记手术其他步骤进行。结果　26例患者经改良Mohs显微描记手术治疗,所有切口均Ⅰ期愈合,皮片或皮瓣均成活,随访1个月～2年,除一例头皮复发性鳞状细胞癌术后一月复发外,余患者均治愈,肿瘤无复发。结论　改良Mohs显微描记手术可指导手术医生更精确地控制扩大切除的范围,在根治肿瘤的同时最大限度的保留正常组织,为下一步的成形修复创造最佳条件。