Isolated sphenoid sinus opacifications (ISSOs) are clinically important because they can lead to serious complications. However, some patients with ISSOs are asymptomatic, and not all patients are properly referred to the otolaryngology department. Because past studies of ISSOs focused only on patients who received treatment, in this study we selected ISSO cases based on radiology reports, then determined whether these patients had symptoms and were appropriately referred for specialty care. We conducted a retrospective analysis of data collected from patients who underwent computed tomography or magnetic resonance imaging from January 2007 to March 2017 at Osaka General Medical Center. We searched for the terms "sphenoid" or "sphenoidal" using F-REPORT to identify patients who had a sphenoid disease. We checked all selected images and diagnosed ISSOs. Examination of 1115 cases revealed 223 cases of ISSOs, of whom 167 (74.9%) were asymptomatic. We categorized patients with ISSOs into four groups: inflammation, mucocele, fungal diseases, and unclassifiable; the final category was used when edges were irregular or complete opacity was encountered. In the unclassifiable group, the majority of cases required otolaryngology consultation, but 37 of 47 unclassifiable patients did not have an otolaryngology visit. ISSOs are often identified by chance on imaging tests performed by non-otolaryngologists. However, our study revealed that many patients with ISSOs who should be treated by otolaryngologists were not referred to the otolaryngology department. Accordingly, it is important to promote awareness of the disease among other types of clinicians.