2.1Introduction

Mohs micrographic surgery can be used to treat a wide variety of tumors. It is well suited for recurrent tumors, those that have been incompletely excised, tumors in high risk anatomical areas, tumors with poorly defined clinical margins, instances of perineural invasion, tumors in immunosuppressed patients, or previously irradiated skin. The tumor should also be continuously growing in both the horizontal and vertical directions; otherwise, falsely clear margins may be observed on horizontal sections [1–3]. In addition, larger tumors greater than 2 cm on the trunk or 1 cm on the face are considered strong indications for Mohs [4–6].

The indications for Mohs micrographic surgery can be divided into common and uncommon varieties. A wealth of data exists for the most common indications, while uncommon indications are mainly supported by case series and reports.

Summary: Common Indications

•Basal Cell Carcinoma (BCC) is the most common indication for Mohs micrographic surgery (MMS).

•MMS has a 99% 5-year cure rate for primary BCC, and a 96% cure rate for recurrent BCC.

2.2Common Indications

2.2.1Basal Cell Carcinoma (BCC)

BCC is not only the most common neoplastic condition but also the most common indication for MMS [4]. MMS has a 99% 5-year cure rate for primary BCC and a 96% cure rate with recurrent tumors [1, 3, 7]. When using standard surgical excision, the long-term recurrence rate for primary BCC is 10.1% [8] and 19.9% for recurrent BCCs treated with non-MMS therapies including radiation, excision, cryosurgery, and curettage [9] (see Table 2.1). The subtypes that are considered especially suitable for MMS are micronodular, morpheaform, metatypical, and infiltrative due to their aggressive nature.

2.2.2Squamous Cell Carcinoma (SCC)

SCC is the second most common indication for MMS [4]. It has a 96.9% cure rate for primary tumors, while standard surgical excision yields a 91.9% cure rate [4]. The recurrence rate for recurrent SCC treated by MMS is 10%, while it is 23.3% when treated with standard surgical excision [10] (see Table 2.1).

The cure rate for SCC is largely dependent upon

trative. They are considered strong indications for MMS.

•Squamous Cell Carcinoma (SCC) is the second most common indication for MMS.

•MMS has a 96.9% cure rate for primary SCC, while it is 23.3% when treated with standard surgical excision.

•The recurrence rate for recurrent SCC treated by MMS is 10%, while it is 23.3% when treated with standard surgical excision.

while those above 2 cm in size have a cure rate of 74.8% [10]. Well-differentiated SCC has a 97% clearance rate using MMS, while poorly differentiated SCC has a 67.4% clearance rate [10]. When using nonMMS treatment, well-differentiated SCC has a cure rate of only 81%, and for poorly differentiated SCC, a cure rate of 46.4% has been reported [10].

SCC in situ is also considered an indication for MMS when located on the face and genitals or when it is greater than 2 cm [4]. The in situ form of SCC, Bowen’s disease, or, if located on the glans penis,