Eosinophilic mucin rhinosinusitis: terminology and clinicopathological presentation

Many terms related to allergic fungal rhinosinusitis (AFRS) such as eosinophilic mucin rhinosinusitis (EMRS), eosinophilic fungal rhinosinusitis (EFRS), and AFRS-like syndrome have been proposed. The authors define EMRS as patients with rhinosinusitis who demonstrate eosinophilic mucin on histopathological examination. EMRS patients who demonstrate fungal hyphae within the mucin are diagnosed as having EFRS and those who cannot demonstrate fungal hyphae within the mucin are diagnosed as having EFRS-like syndrome. EFRS patients who demonstrate an allergic response to the fungi are diagnosed as having AFRS and those who cannot demonstrate any allergic responses to the fungi are diagnosed as having non-allergic fungal rhinosinusitis (NAFRS). In the United States, the prevalence of AFRS in chronic rhinosinusitis patients who require surgery is 5-10 per cent. However, the prevalence of AFRS in Thailand is not known because AFRS has never been reported and studied in Thailand. This study shows the clinical and pathological entities of patients with EMRS in King Chulalongkorn Memorial Hospital from July 2001 to July 2002. From a total of two hundred and fourteen rhinosinusitis patients who required surgery, six were diagnosed as having EMRS. Two of six EMRS patients were diagnosed as having EFRS (both of them were also diagnosed as having AFRS) and four patients were diagnosed as having EFRS-like syndrome. In this study, the prevalence of AFRS is much less than in the United States because of the limited understanding of this disease, the lack of commercially available antigens for dematiaceous fungi, and the lack of awareness and knowledge of pathologists to diagnose eosinophilic mucin and fungi within the mucin. The terms related to AFRS are also discussed in this study.