Approaches to Perineural, Lymphovascular, and Single-Cell Disease

BACKGROUND Mohs micrographic surgeons should be adept in identifying and managing perineural invasion (PNI), lymphovascular invasion (LVI), and single-cell spread (SCS), features denoting high-risk behavior of basal cell carcinoma (BCC), cutaneous squamous cell carcinoma (cSCC) and microcystic adnexal carcinoma (MAC). OBJECTIVE The purpose of this article is to review the literature and guidelines regarding the diagnosis of PNI, LVI, and SCS in BCC, cSCC, and MAC and examine the role of advanced diagnostic studies, adjuvant therapy, and reconstructive techniques of these high-risk tumors. MATERIALS AND METHODS We performed a literature search including the following terms: PNI, LVI, SCS, BCC, cSCC, keratinocyte carcinoma, MAC, sentinel lymph node biopsy, radiation, chemotherapy, and staging. Relevant studies, case reports, and review articles were included, as well as National Comprehensive Cancer Network guidelines. RESULTS Pancytokeratin immunohistochemistry may aid in the diagnosis of high-risk features of BCC and cSCC. Reconstruction of the Mohs defect should be carefully considered to allow for thorough inspection. Radiation therapy should be considered as an adjuvant treatment option for high-risk cSCC and BCC. Close surveillance for recurrence is warranted. CONCLUSION The Mohs surgeon should be competent in identification of high-risk tumors and to understand how best to manage, further treat, and follow these tumors.