A case report of ceruminous adenocarcinoma of the external auditory canal.

Ceruminous adenocarcinoma (CAC) represents an exceedingly rare malignant glandular neoplasm originating from the ceruminous glands within the external auditory canal (EAC), constituting approximately 5%-10% of all EAC malignancies. Owing to its insidious onset and nonspecific symptoms, diagnosis is frequently delayed. This report delineates a case of right EAC CAC in a 39-year-old male, focusing on the diagnostic trajectory, multimodal therapy, and short-term outcomes. The patient presented with a one-month history of recurrent bloody purulent discharge from the right ear, intermittent otalgia, and mild conductive hearing loss. Otoscopy revealed a cauliflower-like, ulcerated, and bleeding mass on the floor of the right EAC. Computed tomography (CT) showed a mass within the right EAC encroaching upon the superficial parotid lobe and the facial nerve's vertical segment, with no intracranial extension. Cervical ultrasound demonstrated multiple enlarged lymph nodes in right levels 2-4. A pathological biopsy confirmed CAC, with immunohistochemical staining positive for CK7, EMA, and partially for S-100. The patient underwent radical surgery, including right subtotal temporal bone resection (with EAC and mastoid removal, reconstructed using temporalis fascia and a skin graft), right total parotidectomy, and right cervical level 2-4 lymph node dissection. Intraoperatively, the tumor infiltrated the facial nerve sheath, but the nerve parenchyma was preserved; the sheath was dissected free without nerve resection or anastomosis. Postoperative adjuvant radiotherapy (60 Gy in 30 fractions) was administered. Recovery was uneventful. At 3-month follow-up, the EAC wound had healed completely, and CT/magnetic resonance imaging showed no residual or recurrent tumor.