An Overlooked Mass in The Nasal Cavity: A Case of Sinonasal Adenoid Cystic Carcinoma

Abstract

Background: Adenoid cystic carcinoma (ACC) is a rare malignant neoplasm of salivary gland origin, accounting for approximately 1% of head and neck malignancies. Sinonasal involvement is uncommon and often presents diagnostic challenges due to its indolent growth, nonspecific symptoms, and late presentation. ACC is characterized by perineural invasion, local aggressiveness, and a propensity for distant metastasis. Case Presentation: We report a case of a 35-year-old male who presented with unilateral left-sided nasal obstruction of one-year duration without epistaxis or facial pain. Diagnostic nasal endoscopy revealed a non-tender, non-bleeding mass arising from the lateral wall of the left nasal cavity. Contrast-enhanced CT and MRI showed a well-defined enhancing lesion originating from the inferior turbinate with preserved bony margins, suggestive of a benign tumor. The patient underwent endoscopic surgical debulking. Histopathological examination demonstrated a cribriform pattern with pseudostratified columnar epithelium, consistent with adenoid cystic carcinoma, without evidence of perineural or lymphovascular invasion. Management and Outcome: Postoperative PET-CT showed low FDG uptake without distant metastasis. The patient received adjuvant external beam radiotherapy using a linear accelerator along with concurrent weekly cisplatin chemotherapy. At six months follow-up, nasal endoscopy and PET-CT showed complete disease clearance. Conclusion: Sinonasal ACC can masquerade as a benign lesion due to its slow growth and subtle presentation. Early diagnosis, surgical debulking, and adjuvant chemoradiation play a crucial role in achieving locoregional control. Long-term follow-up is essential due to the risk of late recurrence and distant metastasis.