Apocrine Carcinoma of the External Auditory Canal: A Rare Case Report

Apocrine carcinoma of the External Auditory Canal (EAC) is an extremely rare malignant neoplasm arising from modified apocrine (ceruminous) glands. We report a 41-year-old man with a long-standing recurrent EAC mass, previously excised multiple times and reported as papillary apocrine cystadenoma and ceruminous adenoma. He presented with progressive conductive hearing loss and a firm swelling occluding the EAC with extension into the temporal region. Imaging showed a large soft-tissue mass filling the canal and involving the temporal soft-tissue and mastoid air cells. Wide excision revealed an invasive tubulopapillary neoplasm with abundant eosinophilic cytoplasm, apocrine snouts, nuclear pleomorphism, mitoses and necrosis. Immunohistochemistry showed diffuse positivity for androgen receptor, GATA-3 and GCDFP-15 with a high Ki-67 proliferative index, confirming apocrine carcinoma. Re-excision with wider margins and selective neck dissection revealed lymph node metastasis and lymphovascular invasion. The patient subsequently received adjuvant radiotherapy. At the time of writing this report, he remains on regular follow-up with no evidence of local recurrence or metastatic disease. This case is notable for its unusual site, occurrence in a relatively young patient and progression from previously benign-reported ceruminous lesions. It highlights the malignant potential of recurrent ceruminous gland tumours and underscores the need for complete excision, thorough histopathological evaluation and long-term surveillance to detect early transformation or recurrence.