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July 3, 2019

Evidence-Based Clinical Practice Guidelines for Microcystic Adnexal Carcinoma: Informed by a Systematic Review

Author Affiliations
  • 1Division of Dermatology, The Ottawa Hospital, Ottawa, Ontario, Canada
  • 2Department of Dermatology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
  • 3Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, New York
  • 4Department of Dermatology, Saint Louis University, St Louis, Missouri
  • 5Department of Dermatology, University of Michigan School of Medicine, Ann Arbor
  • 6Section of Dermatology, Department of Medicine, The University of Chicago, Chicago, Illinois
  • 7Department of Dermatology, Case Western Reserve University School of Medicine, Cleveland, Ohio
  • 8Department of Pathology and Laboratory Medicine, The Ottawa Hospital, Ottawa, Ontario, Canada
  • 9Department of Dermatology, Pennsylvania State University, Hersey
  • 10Division of Oncology, Department of Medicine, Northwestern University Medical Center, Chicago, Illinois
  • 11Department of Surgery, Brigham and Women’s Hospital, Harvard University, Boston, Massachusetts
  • 12Dermatology Service, Memorial Sloan Kettering Cancer Center, New York, New York
  • 13Center for Dermatologic and Cosmetic Surgery, Division of Dermatology, John T. Milliken Department of Internal Medicine, Washington University School of Medicine in St Louis, St Louis, Missouri
  • 14Department of Dermatology, University of California, Davis, Sacramento
  • 15Department of Dermatology, University of Missouri School of Medicine, Columbia
  • 16Department of Dermatology, The University of Alabama at Birmingham
  • 17Department of Dermatology, University of Rochester, Rochester, New York
  • 18Department of Dermatology, University of California, San Diego
  • 19Department of Plastic Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
  • 20Division of Dermatology, Cooper University Hospital Medical Center, Rowan University, Marlton, New Jersey
  • 21Department of Dermatology, Oregon Health & Science University, Portland
  • 22Department of Dermatology, University of Minnesota, Minneapolis
  • 23Department of Dermatology, University Hospitals, Cleveland, Ohio
  • 24Department of Dermatology, Weill Cornell Medicine, Cornell University, New York, New York
  • 25Department of Radiation Oncology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
  • 26Department of Dermatology, University of California, San Francisco
  • 27Division of Mohs and Dermatological Surgery, Department of Dermatology and Cosmetic Dermatology, Henry Ford Hospital, Detroit, Michigan
  • 28Colorado Permanente Medical Group, Denver
  • 29Department of Dermatology, Columbia University Medical Center, New York, New York
  • 30Department of Dermatology, Hospital of the University of Pennsylvania, Philadelphia
  • 31Department of Dermatology, Indiana University School of Medicine, Indianapolis
  • 32Division of Dermatology, Vanderbilt University Medical Center, Nashville, Tennessee
  • 33Department of Otolaryngology–Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
  • 34Department of Dermatology, The University of Texas MD Anderson Cancer Center, Houston
  • 35Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida
  • 36Department of Dermatology, Harvard Medical School, Boston, Massachusetts
  • 37Department of Dermatology, University of Wisconsin–Madison, Madison
  • 38Department of Dermatology, University of Arizona, Phoenix
  • 39Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, Ontario, Canada
JAMA Dermatol. 2019;155(9):1059-1068. doi:10.1001/jamadermatol.2019.1251

Importance  Microcystic adnexal carcinoma (MAC) occurs primarily in older adults of white race/ethnicity on sun-exposed skin of the head and neck. There are no formal guiding principles based on expert review of the evidence to assist clinicians in providing the highest-quality care for patients.

Objective  To develop recommendations for the care of adults with MAC.

Evidence Review  A systematic review of the literature (1990 to June 2018) was performed using MEDLINE, Embase, Web of Science, and the Cochrane Library. The keywords searched were microcystic adnexal carcinoma, sclerosing sweat gland carcinoma, sclerosing sweat duct carcinoma, syringomatous carcinoma, malignant syringoma, sweat gland carcinoma with syringomatous features, locally aggressive adnexal carcinoma, and combined adnexal tumor. A multidisciplinary expert committee critically evaluated the literature to create recommendations for clinical practice. Statistical analysis was used to estimate optimal surgical margins.

Findings  In total, 55 studies met our inclusion criteria. The mean age of 1968 patients across the studies was 61.8 years; 54.1% were women. Recommendations were generated for diagnosis, treatment, and follow-up of MAC. There are 5 key findings of the expert committee based on the available evidence: (1) A suspect skin lesion requires a deep biopsy that includes subcutis. (2) MAC confined to the skin is best treated by surgery that examines the surrounding and deep edges of the tissue removed (Mohs micrographic surgery or complete circumferential peripheral and deep margin assessment). (3) Radiotherapy can be considered as an adjuvant for MAC at high risk for recurrence, surgically unresectable tumors, or patients who cannot have surgery for medical reasons. (4) Patients should be seen by a physician familiar with MAC every 6 to 12 months for the first 5 years after treatment. Patient education on photoprotection, periodic skin self-examination, postoperative healing, and the possible normal changes in local sensation (eg, initial hyperalgesia) should be considered. (5) There is limited evidence to guide the treatment of metastasis in MAC due to its rarity. Limitations of our findings are that the medical literature on MAC comprises only retrospective reviews and descriptions of individual patients and there are no controlled studies to guide management.

Conclusions and Relevance  The presented clinical practice guidelines provide an outline for the diagnosis and management of MAC. Future efforts using multi-institutional registries may improve our understanding of the natural history of the disease in patients with lymph node or nerve involvement, the role of radiotherapy, and the treatment of metastatic MAC with drug therapy.