An extraosseous dermoid cyst of maxilla: a rare case report and review of literature

Abstract Background Dermoid cysts involving the maxillofacial region are uncommon with primary involvement of the maxilla being exceptionally rare. To date, only three cases of maxillary dermoid cysts have been reported in the literature. To the best of our knowledge, this represents the first reported case of an extraosseous maxillary dermoid cyst, underscoring the exceptional rarity and uniqueness of this entity. The case posed significant diagnostic challenges, particularly in accurately delineating the precise anatomical plane of origin and characterizing the lesion’s internal contents on radiologic evaluation. Also, an updated review of dermoid cysts arising in deep facial spaces, skull base, and bony compartments of the maxillofacial region, highlighting their varied clinical presentations and management strategies, is included. Case presentation A 28-year-old male presented with chronic right-sided facial pain. He was previously diagnosed and treated outside for chronic rhinosinusitis. With computed tomography (CT) and magnetic resonance imaging (MRI), a benign cyst with punctate calcifications with fat-predominant contents in the subperiosteal plane protruding into the pterygopalatine fossa (PPF) was identified. An endonasal endoscopic surgery was performed and a cyst with cheesy keratinous material was removed completely. A histopathology confirmed the diagnosis of a dermoid cyst. Conclusions Both CT and MRI are indispensable modalities for accurate localization and characterization of cystic lesions arising in the deep spaces of maxillofacial region. Subtle imaging findings, particularly the presence of hypointense rim on T1-weighted images (T1WI), were instrumental in suggesting a posterior-maxillary origin rather than a true PPF lesion. The fat-suppression MRI sequence (FS-T2WI) being able to demonstrate the co-existence of lipid content and punctate calcifications was the decisive imaging sequence that helped us narrow the diagnosis in favor of a dermoid cyst. Nevertheless, histopathological examination was essential for establishing a definitive diagnosis. Histopathological examination was essential for a definitive diagnosis. Surgically, the endoscopic endonasal approach provided excellent access with minimal morbidity, enabling superior visualization, complete excision, rapid postoperative recovery, and effective postoperative surveillance.