Microcystic adnexal carcinomaMicrocystic adnexal carcinoma (MAC) is a rare adnexal tumor which is often found on the head and neck and usually presents as an ill-defined, yellowish or faintly erythematous plaque. It is characterized by aggressive local infiltration and has a high propensity for perineural invasionPerineural invasion (PNI). Most cases have been reported in white patients aged 40–60 years, and there is no sexual predilection. The tumor also occurs in other ethnic groups and across a much wider age range. An incisional biopsy extending to the fat is usually necessary for diagnosis. Surgery is the treatmentTreatment of choice. The poorly defined clinical marginsClinical margins and propensity for perineural spread make Mohs micrographic surgeryMohs micrographic surgery (MMS) preferable to standard surgical excisionSurgical excision (SSE). When nerve involvement is present, MMS with formalin-fixed, paraffin-embedded sections should be considered. The prognosis is good and the 10-year survival rate seems to vary between 68 and 87%, depending on the initial size and site of the tumor. Periocular MAC is at higher risk of recurrence.