Abstract
OBJECTIVES: The frequency of paranasal sinus fungus balls, a common form of rhinosinusitis, has increased. Although treatment and causative factors have been well investigated, the evolving nature of the fungal balls remains unelucidated. This study aimed to investigate and analyze the changing patterns of fungus balls. METHODS: This retrospective study analyzed data from 35 participants selected from a pool of 41,497 patients who underwent brain magnetic resonance imaging (MRI) at a large health care center. The extent of the fungus balls was evaluated by grading them from 1 to 4 based on the MR images. The changing process of the fungus ball was analyzed based on demographics, interval between the MRI scans, comorbidities, and specific dental interventions. RESULTS: The fungus ball grades showed significant progression over time. In the analysis of 29 sinuses with initially low-grade (grades 0, 1, and 2) fungus balls, 15 sinuses showed a grade change <2 (no/minimal change group), whereas 14 sinuses showed grade changes of ≥2 (substantial change group). Intergroup comparison showed that only the interval between the initial and final MRI scans differed significantly (p = 0.008). However, factors, such as age, sex, comorbidities, and history of dental procedures, did not differ significantly between the two groups. CONCLUSION: This study shows the extent of change in fungus balls, primarily over time. These results offer critical insights into the natural course and progression of the maxillary sinus fungus ball. LEVEL OF EVIDENCE: 4 Laryngoscope, 135:1315-1320, 2025.