Unusual Manifestations of Sinonasal Osteomas: A Narrative Review

Background/Objectives: Sinonasal osteomas are benign, slow-growing tumors that are typically asymptomatic and incidentally detected. However, in rare cases, they may present with atypical and potentially serious complications involving other sinonasal, orbital, or intracranial structures. This review aims to synthesize these unusual manifestations and to highlight the underlying mechanisms, diagnostic challenges, and management implications. Methods: A narrative review of the literature was conducted, focusing on reported cases of sinonasal osteomas with rare or complicated presentations. Studies were analyzed with emphasis on clinical features, imaging findings, pathophysiological mechanisms, and treatment strategies. Results: Unusual presentations of sinonasal osteomas are primarily driven by sinus obstruction, progressive expansion, and skull-base erosion. These processes may result in complications such as pneumocephalus, intracranial mucoceles, cerebrospinal fluid leaks, orbital compression, and secondary infections. Clinical manifestations are often nonspecific, including headache, seizures, visual disturbances, or focal neurological deficits, which may delay diagnosis. High-resolution computed tomography is essential for identifying the osseous lesion and associated bone changes, while magnetic resonance imaging is critical for assessing soft-tissue involvement and intracranial extension. Management is individualized, with surgical resection indicated in most symptomatic or complicated cases, using endoscopic, open, or combined approaches. Conclusions: Although rare, atypical manifestations of sinonasal osteomas can result in significant morbidity. A mechanism-based understanding, supported by appropriate imaging, is essential for accurate diagnosis and timely management. Increased clinical awareness is crucial to improving outcomes in these uncommon but clinically significant cases.