Background: Mohs micrographic surgery (MMS) is used for treatment of primary and recurrent tumors. Compared with primary tumors, recurrent tumors are often more aggressive.
Objective: To understand differing characteristics between primary versus recurrent tumors treated by MMS.
Materials and methods: The authors conducted a retrospective review of a 12-year period at 1 academic center. Recurrent tumors were defined as recurrent if previously treated with cryotherapy, topical chemotherapeutics, electrodesiccation and curettage, or excision. Statistical analysis was conducted with p ≤ .05 considered significant.
Results: A total of 17,971 cases were reviewed, of which 10.5% represented recurrent tumors. Recurrent tumors occurred more commonly in men (ratio 2.2:1). They presented in older individuals (p < .01) and occurred more commonly on the scalp (p < .0001), neck (p < .0001), and trunk (p < .0001). Primary tumors were more commonly located on the periocular (p < .0001), nose (p < .0001), and perioral areas (p < .0001). Squamous cell carcinoma more commonly presented as primary tumors (p = .02) while squamous cell carcinoma in situ more commonly presented as recurrent tumors (p < .001).
Conclusion: Distinct characteristics separate primary and recurrent tumors treated by MMS. Primary tumors were more commonly located in Area H, compared with recurrent tumors, which were more commonly located in Area M. This suggests appropriate usage of MMS based on appropriate use criteria.