BACKGROUND. Signal void, or the absence of signal on MRI sequences, in the sinonasal region may be encountered in fungal rhinosinusitis cases with the aspect of a pseudo-pneumatized sinus, leading to diagnostic errors.
CASE REPORT. We present the case of a 75-year-old woman referred to our clinic for complete and persistent right-sided nasal obstruction. The patient was evaluated using sinus CT and contrast-enhanced head MRI. Opacification of the right maxillary, ethmoid and frontal sinuses as well as of the right nasal fossa were seen on CT, with maxillary sinus expansion and osseous erosion. The MRI showed T2 signal void in the maxillary sinus with extension to the nasal fossa, creating the appearance of a pseudo-pneumatized sinus, and hyperintense signal in the ipsilateral anterior ethmoid and frontal sinuses. The patient underwent endoscopic sinus surgery. The dual imaging evaluation of the patient aided the preoperative differential diagnosis and choosing the surgical approach.
