Histopathological changes in the maxillary sinus mucosa in fungal balls

Fungal balls refer to non-invasive forms of fungal rhinosinusitis and can be asymptomatic for a long time. Objective. To investigate pathomorphological changes in the maxillary sinus mucosa in fungal balls. Material and methods. The results of histological examination of intraoperative samples obtained during endonasal endoscopic sinus surgery of 74 patients were analyzed. Patients with odontogenic processes were excluded from the study. Histological examination was performed on sinus contents and biopsy specimens of the sinus mucosa from the loci of adjoining fungal balls. Results. Histological examination of the caseous contents of the operated sinuses has revealed mycelial accumulations of different maturity degrees, containing degenerating areas with microbial colonies. Cellular infiltration of the lamina propria of the mucosa by lymphomacrophagal cells with polymorphonuclear leukocytes, plasma cells and a significant number of eosinophils indicates the presence of chronic inflammation. Subepithelially located fungal hyphae without angioinvasion were found in one sample. Conclusion. Fungal balls of the paranasal sinuses cause the development of chronic inflammation in the mucosa even in asymptomatic disease course and should be removed surgically due to the possibility of their transformation into invasive mycoses.