Purpose: Many physicians recommend endoscopic sinus surgery (ESS) even when an asymptomatic paranasal sinus (PNS) fungal ball is detected incidentally. The aim of this study was to investigate the natural behavior of PNS fungal balls via sinus imaging techniques.
Methods: A follow-up study of 74 pathologically confirmed fungus balls was conducted in 70 patients who underwent multiple head and neck computed tomography (CT) scans or magnetic resonance imaging (MRI). We investigated the changes in symptoms and lesion size, as well as any new occurrences.
Results: Of the 74 fungus balls detected in 70 patients, we observed the renewed formation of a fungal ball in 21 patients, which was not present on initial imaging conducted over a period of 2-162 months. The fungal ball was already present in 53 patients on the initial screening, and the longest follow-up was 197 months (range 1-197 months). Of these 53 lesions, 29 lesions showed an increase in size (29/53, 54.7%), whereas 12 lesions were not associated with any clinical symptoms (12/53, 22.6%). In the 21 newly formed fungal balls, further development was observed in 10 lesions, with 4 lesions showing an increase in size. Thus, size increment occurred in 33 of the 57 fungus balls.
Conclusions: The fungal balls can exist without local tissue invasion for up to 17 years and new formation of the fungal balls was observed even within 2 months, especially when accompanied by initial clinical symptoms of sinusitis.
Keywords: Clinical course; Fungal ball; Fungal sinusitis; Treatment plan.