Pleomorphic Adenoma of the External Auditory Canal From Ceruminous Gland Adenoma: Case Report and Review of the Literature.

We describe a right external auditory canal (EAC) recurrent ceruminous pleomorphic adenoma (CPA) accompanied by itching and review the clinical features and histopathology of this disease. A female in her 70s presented with a right EAC mass accompanied by itching. We initially diagnosed the mass as a ceruminous gland adenoma (CGA) following excisional biopsy. Two years and nine months later, the tumor recurred at the same site. A preoperative computed tomography (CT) scan demonstrated no bone destruction, and magnetic resonance imaging (MRI) showed a 1 × 1 cm mass with a clearly defined margin in the right EAC. We completely excised the recurrent tumor using a transmeatal approach under general anesthesia. Histopathology demonstrated haphazard proliferation of tubule-glandular structures lined by two layers of the epithelium in the hypocellular stroma composed of a mucoid matrix. The recurring tumor was diagnosed as a CPA. Here, an EAC tumor-originally diagnosed as a CGA following excisional biopsy-recurred and was subsequently diagnosed as a CPA. CPA can be considered an unusual variant of CGA.