Appropriate Use Criteria for Mohs Surgery

Overview / DefinitionMohs micrographic surgery is a precise surgical technique used to treat certain types of skin cancer, primarily basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). The procedure involves the stepwise excision of cancerous tissue while preserving as much healthy tissue as possible, allowing for immediate microscopic examination to ensure complete removal of cancer cells.EpidemiologySkin cancer is the most common form of cancer in the United States, with over 5 million cases treated annually. Basal cell carcinoma accounts for approximately 80% of non-melanoma skin cancers, while squamous cell carcinoma accounts for about 16%. Mohs surgery is particularly beneficial in high-risk areas, including the face, ears, and hands, where cosmetic outcomes are crucial.Pathophysiology / MechanismBasal cell and squamous cell carcinomas originate from keratinocytes in the epidermis. The carcinogenesis is often attributed to cumulative ultraviolet (UV) radiation exposure, leading to DNA damage. The Mohs technique employs a histological evaluation of excised tissue at each stage, allowing for the identification of residual cancerous cells and ensuring complete clearance.Clinical PresentationPatients with basal cell carcinoma may present with:Pearly nodules with telangiectasiaCentrally ulcerated lesionsScaly plaques that may bleed or crustSquamous cell carcinoma may appear as:Firm, red nodulesScaly patches that may crust or bleedNon-healing ulcersDiagnosis / WorkupThe diagnosis of skin cancer is primarily clinical, often supplemented by:Dermatoscopy for enhanced visualizationBiopsy to confirm the diagnosis and assess the depth of invasionImaging studies are typically not required unless there is suspicion of metastasis or deeper invasion.Treatment / ManagementMohs micrographic surgery is indicated in the following scenarios:High-risk non-melanoma skin cancers (e.g., recurrent BCC/SCC)Cancers located in cosmetically sensitive areasLarge tumors or those wit