Specific imaging findings in the course of sinus fungus ball progression to chronic invasive fungal rhinosinusitis

Scattered reports have found that sinus fungus ball (SFB) may progress to chronic invasive fungal rhinosinusitis (CIFRS), but the mechanism is not yet understood. Distinguishing between SFB and CIFRS is sometimes tricky. The invasive features of CIFRS make the symptoms and imaging findings indistinguishable from those of malignant tumors. We herein report a case in which a patient was examined and treated very early in the transition from SFB to CIRFS. An 81-year-old woman with CIFRS was treated with surgery and Voriconazole. Computed tomography (CT) showed a typical high-intensity mass in the maxillary sinus and bony hypertrophy with unusual bony erosion. Magnetic resonance imaging (MRI) showed clear contrast between edematous mucosa and mucosa with CIFRS. The diffusion coefficient (ADC) value in particular was limited to a portion of the CIFRS lesion. The ADC value is helpful as a reference for evaluating the transition of SFB to CIFRS.

Automated summary

This article reports a case of early transition from sinus fungus ball to chronic invasive fungal rhinosinusitis. CT and MRI imaging can help distinguish between these two diseases, and the ADC value can be used as a reference for evaluating the transition.