Endoscopic Management of Primary Adenoid Cystic Carcinoma of the Nasal Septum: A Case Report and Literature Review.

Adenoid cystic carcinoma (ACC) of the nasal septum is an exceedingly rare malignancy characterized by indolent but aggressive growth, frequent perineural invasion, and late-onset distant metastasis. Preoperative diagnosis can be challenging due to histopathologic similarities with benign salivary-type tumors. We report the case of a 75-year-old woman who presented with nasal obstruction and intermittent epistaxis. Nasal endoscopy identified a polypoid mass on the posterior nasal septum, and biopsy initially suggested a basal cell adenoma. Imaging revealed no evidence of perineural spread or skull base invasion. The patient underwent endoscopic resection with negative intraoperative margins. Final histopathological analysis confirmed cribriform-pattern ACC without perineural invasion. Given the patient's comorbidities and family preference, adjuvant radiotherapy was not administered. Although the early postoperative course was uneventful, the patient developed local recurrence and cervical spine metastasis 52 months after surgery. She declined further treatment but remained alive with the disease at 72 months under observation. This case underscores the diagnostic complexity of nasal septum ACC and demonstrates the utility of endoscopic resection for localized tumors. However, in light of the delayed recurrence and close surgical margins typical of endoscopic approaches, the role of adjuvant radiotherapy should be carefully evaluated on an individual basis. Long-term follow-up is essential due to the potential for late recurrence and distant metastasis.