INTRODUCTION
Skin cancer is the most common form of cancer in the United States, and the incidence has risen drastically in the last decade. From 2006 to 2012 alone, the annual number of nonmelanoma skin cancer (NMSC) increased from 3.5 million to 5.4 million.1,2 In the same period, the number of procedures for skin cancer increased by 56%.1,3 Fortunately, there are many effective treatments for skin cancer including Mohs micrographic surgery (MMS).4
MMS is a frozen section-assisted excisional technique utilizing microscopically controlled surgical margins. Compared to conventional radical surgical approaches (partial or total penectomy, vulvectomy, wide local excision), MMS offers distinct advantages in the genitalia. The primary advantage is minimizing tissue loss, which could be functionally and aesthetically devastating in the genital area. Another advantage is lower long-term recurrence rates. Because the incidence of genital skin cancer has increased by approximately 30% in recent years, a thorough understanding of the benefits and risks of MMS for genital NMSC is necessary.5
The aim of this article is to provide an overview of NMSCs arising on genital skin treated with MMS, and describe some of their indications, results, and associated complications. A summary of case reports, case series, and retrospective reviews is made available to guide decision making and surgical planning for tumors of this nature. Pertinent anatomy, site-specific surgical techniques, and reconstruction options of genital skin will be discussed.
Squamous Cell Carcinoma
In the United States, squamous cell carcinoma (SCC) accounts for most genital cancers (>95%), followed by less common tumors such as basal cell carcinoma (BCC), extramammary Paget’s disease (EMPD), and soft tissue sarcomas.6,7 In men, the majority of penile cancers (95%) are of squamous epithelial origin, including in situ and invasive SCC.7–10 Similarly, in women vulvar skin cancers are predominantly invasive SCC.11,12 Important predisposing factors include lack of circumcision, poor hygiene, phimosis, chronic inflammation, psoralen plus ultraviolet A (PUVA) phototherapy, tobacco use, and malignant transformation of human papillomavirus (HPV) infection.7,9
Clinically, genital carcinomas can manifest as squamous cell carcinoma in situ (SCCIS) characterized by erythematous, well-demarcated scaly patches or plaques, invasive SCC presenting as indurated plaques or nodules with areas of ulceration, or verrucous carcinoma appearing as exophytic cauliflower-like locally destructive masses. The goal of treatment is to achieve complete tumor cell clearance while limiting anatomic disfigurement. Compared to non-surgical interventions such as cryosurgery, electrodesiccation and curettage, laser ablation, photodynamic therapy, and topical imiquimod or 5-fluorouracil creams, surgical excision has the advantage of providing tissue for pathologic grading and margin assessment. Traditionally, a 2 cm margin has been recommended in wide local excisions of genital SCC to minimize recurrence.7,13 However, recent studies suggest that a 2cm surgical margin may not be necessary for margin control as long as intraoperative frozen sections are negative.14–16
MMS is a frozen section-assisted excisional technique utilizing microscopically controlled surgical margins. Compared to conventional radical surgical approaches (partial or total penectomy, vulvectomy, wide local excision), MMS offers distinct advantages in the genitalia. The primary advantage is minimizing tissue loss, which could be functionally and aesthetically devastating in the genital area. Another advantage is lower long-term recurrence rates. Because the incidence of genital skin cancer has increased by approximately 30% in recent years, a thorough understanding of the benefits and risks of MMS for genital NMSC is necessary.5
The aim of this article is to provide an overview of NMSCs arising on genital skin treated with MMS, and describe some of their indications, results, and associated complications. A summary of case reports, case series, and retrospective reviews is made available to guide decision making and surgical planning for tumors of this nature. Pertinent anatomy, site-specific surgical techniques, and reconstruction options of genital skin will be discussed.
Squamous Cell Carcinoma
In the United States, squamous cell carcinoma (SCC) accounts for most genital cancers (>95%), followed by less common tumors such as basal cell carcinoma (BCC), extramammary Paget’s disease (EMPD), and soft tissue sarcomas.6,7 In men, the majority of penile cancers (95%) are of squamous epithelial origin, including in situ and invasive SCC.7–10 Similarly, in women vulvar skin cancers are predominantly invasive SCC.11,12 Important predisposing factors include lack of circumcision, poor hygiene, phimosis, chronic inflammation, psoralen plus ultraviolet A (PUVA) phototherapy, tobacco use, and malignant transformation of human papillomavirus (HPV) infection.7,9
Clinically, genital carcinomas can manifest as squamous cell carcinoma in situ (SCCIS) characterized by erythematous, well-demarcated scaly patches or plaques, invasive SCC presenting as indurated plaques or nodules with areas of ulceration, or verrucous carcinoma appearing as exophytic cauliflower-like locally destructive masses. The goal of treatment is to achieve complete tumor cell clearance while limiting anatomic disfigurement. Compared to non-surgical interventions such as cryosurgery, electrodesiccation and curettage, laser ablation, photodynamic therapy, and topical imiquimod or 5-fluorouracil creams, surgical excision has the advantage of providing tissue for pathologic grading and margin assessment. Traditionally, a 2 cm margin has been recommended in wide local excisions of genital SCC to minimize recurrence.7,13 However, recent studies suggest that a 2cm surgical margin may not be necessary for margin control as long as intraoperative frozen sections are negative.14–16
