Microcystic Adnexal Carcinoma: A Review of the Literature

BACKGROUND Microcystic adnexal carcinoma (MAC) is a rare, locally aggressive cutaneous neoplasm that commonly occurs on the face. OBJECTIVE The purpose of this article is to comprehensively review the current literature on MAC pertaining to epidemiology, pathogenesis, clinical presentation, histology, immunohistochemistry, prognosis, follow-up, and treatment. MATERIALS AND METHODS An extensive literature review was conducted using OVID MEDLINE and PubMed to identify articles relating to MAC. RESULTS Microcystic adnexal carcinoma typically presents as a skin-colored nodule on the face. The pathogenesis is mostly related to pilar and eccrine differentiation. Histologically, MAC can mimic syringoma, desmoplastic trichoepithelioma, and infiltrative basal cell carcinoma. Diagnosis is challenging because superficial shave biopsies may reveal only benign findings that do not warrant further management. A deep biopsy is mandatory for the correct diagnosis, and Mohs micrographic surgery provides the highest cure rate. CONCLUSION Microcystic adnexal carcinoma is a locally aggressive disease with histological margins that often far surpass what is clinically suspected. Mohs micrographic surgery is the standard of care for removal of these lesions. Patients with a history of MAC should be examined at least every 6 months for recurrence, metastasis, and development of additional skin cancers.