Adenoid Cystic Carcinoma of the Ethmoid Sinus Presenting as Proptosis: A Rare Case Report

Abstract

Adenoid cystic carcinoma (ACC) of the ethmoid sinus is a rare and locally aggressive malignancy that may present with orbital manifestations due to direct extension. We report a case of a 49-year-old female who presented with progressive unilateral proptosis, diminution of vision, nasal obstruction, facial pain, and headache. Clinical examination revealed eccentric proptosis, restricted ocular motility, and relative afferent pupillary defect in the left eye. Magnetic resonance imaging demonstrated a heterogeneously enhancing mass centered in the left ethmoid sinus with orbital and intracranial extension, erosion of the cribriform plate, and compression of adjacent orbital structures. The patient underwent multidisciplinary management with endoscopic biopsy, tumor debulking, and surgical resection. Histopathological examination confirmed adenoid cystic carcinoma with a predominant cribriform pattern and perineural invasion. Adjuvant radiotherapy was advised. This case highlights the importance of considering sinonasal malignancies in patients presenting with atypical unilateral proptosis and emphasizes the role of imaging, histopathology, and multidisciplinary management in achieving timely diagnosis and treatment.