An Overview of Mohs Micrographic Surgery for the Treatment of Basal Cell Carcinoma Lance D. Wood, MD*, Christie T. Ammirati, MD MOHS MICROGRAPHIC SURGERY IN THE MANAGEMENT OF BASAL CELL CARCINOMA Basal Cell Carcinoma Basal cell carcinoma (BCC) makes up about 80% of all skin cancers, and it has been estimated that approximately 1 in 4 Americans will develop BCC during their lifetime. 1 BCC is highly associated with ultraviolet radiation exposure, and as such, the most common locations for it to develop are the head and neck (Box 1). 2 Although BCCs are usually asymptomatic and only rarely metastasize, if left untreated, they can lead to significant func- tional and cosmetic morbidity (Figs. 1 and 2). 3 In general, treatment of this slow-growing and rarely metastasizing type of skin cancer is simple and straightforward, particularly for lesions on the trunk and extremities. In these locations, tech- niques such as curettage (often in combination with electrodesiccation or cryosurgery) or simple surgical excision can provide high cure rates. 4 However, treatment can be more challenging in cosmetically sensitive locations such as the head, neck, and genital area. In these regions, it is particularly crucial to both completely remove the neoplasm, thus limiting recurrence, and preserve function and appearance as much as possible. These requirements have led to the development of Mohs micrographic surgery (MMS) as the most widely accepted treatment of BCC in areas with the greatest demand for tissue preservation and those at greatest risk for recurrence. 5–8 MMS As it is practiced today, MMS has evolved signifi- cantly from its first description as chemosurgery by Dr Frederic Mohs in 1941. 9 Initially, his tech- nique involved direct injections of zinc chloride solution into the tumor and surrounding area for in vivo tissue fixation. After 12 to 24 hours, the involved tissue was removed from an often blood- less field for microscopic examination. However, instead of traditional vertical sections, the tissue was oriented into tangential sections, which exam- ined the entire peripheral and deep margins and led to cure rates approaching 99%. 9–11 Over time, Dr Mohs and others contributed to advancement in the field by introducing the removal of fresh tissue under local anesthesia for evaluation. 12,13 In 1970, Dr Theodore Tromovitch presented the first series of patients using the fresh tissue technique. This series was followed by another supporting study by Tromovitch and Stegman 14 in 1974. Both these studies illustrated success rates that were comparable to the previ- ously described fixed tissue technique, opening the door to all of the potential benefits of using the fresh tissue technique without sacrificing the excellent outcomes that were achieved with the The authors have nothing to disclose. Penn State Hershey Department of Dermatology, Penn State Milton S. Hershey Medical Center, 500 University Drive, PO Box 850, Hershey, PA 17033-0850, USA * Corresponding author. E-mail address: lwood@hmc.psu.edu KEYWORDS  Basal cell carcinoma  Mohs micrographic surgery  Skin cancer Dermatol Clin 29 (2011) 153–160 doi:10.1016/j.det.2011.02.005 0733-8635/11/$ – see front matter Ó 2011 Elsevier Inc. All rights reserved. derm.theclinics.com