Diagnosis and Management of Seborrheic Keratosis of the External Auditory Canal: A Systematic Review

Objectives To perform an evidence‐based review evaluating the presenting symptoms, diagnostic tools, and management of seborrheic keratosis involving the external auditory canal. Data Sources PubMed, Embase, EBM Reviews, and Web of Science databases. Review Methods A systematic review following Preferred Reporting Items for Systematic Reviews and Meta‐Analysis reporting guidelines was conducted to identify publications pertaining to seborrheic keratosis of the external auditory canal from four databases. The primary outcomes extracted from publications include presenting symptoms, diagnostic testing, management strategies, and recurrence rate. Results A total of 18 studies met inclusion criteria describing 24 patients and 25 external auditory canals with seborrheic keratosis (one patient had bilateral disease). The most common presenting symptoms included a clinically evident mass involving the external auditory canal (52%), otorrhea (28%), and decreased hearing (24%). Biopsy of the external auditory canal mass was performed in 11 cases (44%). Most lesions were treated via surgical excision (84%) or electrocautery (8%). Final histopathology of excised specimen demonstrated squamous cell carcinoma among two cases (8%) and basal cell carcinoma in one case (4%). There were five cases (26%) of tumor recurrence among the 19 cases which reported follow‐up. Both cases treated with electrocautery alone were found to have recurrence at follow up. Conclusion While usually benign, seborrheic keratosis has a propensity for malignant transformation. Incisional biopsy can help narrow the differential diagnosis and aid management. Surgical resection is recommended to lessen the risk of tumor recurrence.