Differences in clinical and imaging presentation of maxillary sinus fungus ball with and without intralesional hyperdensity

Maxillary sinus fungal balls (MSFBs) mostly occur in older individuals and demonstrate female predominance. Early diagnosis is important to avoid treatment delays. Intralesional hyperdensity (IH) indicates the presence of heavy metal deposition within fungal hyphae and has been the most specific characteristic of MSFB on computed tomography (CT). For those without IH on CT, the diagnosis of MSFB remains challenging. This study aimed to characterize clinical presentation of MSFB with and without IH and to study factors contributing to MSFB with no IH formation. We retrospectively identified 588 patients with MSFB. The clinical characteristics and CT findings were reviewed. Patients with unilateral MSFB had a mean age of 57.4 years and demonstrated female predominance (64.63%). The female-to-male ratio was highest at 51–60 years (2.02) and rose to 2.60 in MSFB with IH only. Compared to those with IH, MSFB without IH was significantly more common in males (OR = 2.49), in those with diabetes mellitus (DM) (OR = 1.87), adjacent maxillary odontogenic pathology (OR = 1.75). Complete opacification on CT was less common in MSFB without IH (OR = 0.60). Patients with MSFB without IH were more likely to have DM, no female predominance, adjacent maxillary odontogenic pathology, and partial opacification of the sinus, compared to those with IH. These may be helpful in better understanding of the formation of MSFBs without IH, early identification of them and prevention of post-operative recurrence.