Hidradenocarcinoma: A Case Series From the Scripps Clinic With a Systematic Review of the Literature

BACKGROUND Hidradenocarcinoma (HAC) is a rare adnexal carcinoma. To the best of the authors' knowledge, there are no published systematic reviews on HAC. OBJECTIVE To incorporate a case series from the authors' institution and systematically integrate reported information to provide a reference tool for optimization of diagnosis and management. METHODS A comprehensive MEDLINE search was conducted from database inception to 2021 using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. This yielded 225 studies with 165 cases of HAC. References of included articles were also searched. In addition, 9 patients with HAC were identified from the authors' institution over the past 10 years. RESULTS The mean age of HAC presentation is 60 years with a slight male predilection (60%). The head and neck is the most commonly affected region. Over 36% of cases either presented with metastatic disease or went on to metastasize. The most common treatment type was wide local excision, followed by Mohs micrographic surgery. CONCLUSION Early detection with accurate histologic interpretation is prudent in all cases of HAC. Wide local excision is the current first-line treatment. However, Mohs micrographic surgery offers complete marginal analysis with evidence of reduced risk of metastasis and better outcomes compared with wide local excision. Currently, there are no National Comprehensive Cancer Network guidelines for the treatment of HAC, and consensus guidelines are limited to tumor and nodal metastasis staging provided by the American Joint Committee on Cancer, eighth edition. Thus, this case series and systematic review integrates important aspects of diagnosis, workup, and management of HAC.