Introduction
AFRS is non-invasive fungal sinusitis recognized in 19761, which is a subset of polypoid CRS that is
characterized by the presence of eosinophilic mucin with non-invasive
fungal hyphae within the sinuses and a type I hypersensitivity to fungi.
In 1993, Bent and Kuhn proposed the diagnostic criteria of AFRS based on
the prospective study of 15 patients 2. These major
criteria consist of the following: 1. Nasal polyposis; 2. Fungi on
staining; 3. Eosinophilic mucin without fungal invasion into sinus
tissue; 4. Type I hypersensitivity to fungi and; 5. Characteristic
radiology findings with soft tissue differential densities on CT
scanning and unilaterality or anatomically discrete sinus involvement.
The minor
criteria
include bone erosion, Charcot Leyden Crystals, unilateral disease,
peripheral eosinophilia, positive fungal culture and the absence of
immunodeficiency or diabetes 3. The European position
paper on rhinosinusitis and nasal polyps (EPOS) 2020 steering group
discussed whether the term ‘eosinophilic fungal rhinosinusitis’ would be
a better umbrella term but it was agreed that ‘allergic fungal
rhinosinusitis’ should be retained as the principal term due to common
usage, recognizing that not all cases have evidence of an allergic
reaction to fungi 4.
AFRS has a high recurrence rate. It often requires two or more surgical
treatments, but it is still difficult to achieve a satisfactory
therapeutic effec5, 6. Delays in misdiagnosis may even
lead to serious complications, including loss of smell, loss of vision,
blindness, cranial nerve lesions, intracranial abscess or cavernous
sinus syndrome 7-12. In serious cases, fungi may even
turn into an invasive infection, resulting in patient
death11. In order to investigate the incidence and
improve the understanding of AFRS, we reread discharge and operative
records, radiographic imaging, laboratory and pathological reports of
CRS patients treated in our center from January 2015 to December 2020.