Ectopic Pleomorphic Adenoma: A Case Study and Scoping Review of the Literature

We present a case of an ectopic pleomorphic adenoma occurring in the glabellar region of an adult patient and perform the first known scoping review of the literature on ectopic pleomorphic adenomas of the head and neck, seeking to summarize their symptomatology, presentation, and treatment. Two independent reviewers performed searches and qualitative synthesis of relevant literature using PubMed, Embase, and Ovid All EBM Review databases. The authors adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses-Scoping Review (PRISMA-ScR) statement. Included studies reported ectopic pleomorphic adenoma originating above the clavicle. Exclusion criteria included tumors as a result of metastasis or of non-salivary gland origin. Forty-six case series and case reports of ectopic pleomorphic adenomas met the inclusion and exclusion criteria, for a total of 48 tumors. Most cases occurred during the 2nd to 6th decades of life with a male:female ratio of 1:1.2. Ectopic pleomorphic adenomas typically presented as a slow-growing, firm, mobile mass on a superficial region of the head or neck. Pain was reported in 19% of cases. All cases were treated with surgical excision, and there was only one recurrence after a malignant transformation.