Categorization and Clinicopathological Features of Chronic Rhinosinusitis With Eosinophilic Mucin in a Korean Population

OBJECTIVES Chronic rhinosinusitis (CRS) with eosinophilic mucin is relatively rare in Korea. We categorized CRS patients with characteristic eosinophilic mucin into several groups and compared the groups based on their clinicopathological features. METHODS In total, 52 CRS patients with eosinophilic mucin were enrolled. Based on the presence or absence of an allergy (A) to a fungus or fungal element (F) in the mucin, the patients were divided into four groups: allergic fungal rhinosinusitis (AFRS, A+F+), AFRS-like sinusitis (A+F-), eosinophilic fungal rhinosinusitis (EFRS, A-F+), and eosinophilic mucin rhinosinusitis (EMRS, A-F-). Clinical and immunological variables were compared between the groups. RESULTS There were 13 patients in the AFRS group, 13 in the EFRS group, and 26 in the EMRS group. No patient was assigned to the AFRS-like sinusitis group. The AFRS group showed a significantly higher association with allergic rhinitis than did the EFRS and EMRS groups. The mean total serum IgE level in the AFRS patients was significantly higher than in the EFRS and EMRS patients. While 7.7% of the patients with AFRS and EFRS were asthmatic, 65.4% of the patients with EMRS had bronchial asthma. In the AFRS and EFRS groups, 31% had bilateral disease, in contrast to 100% of EMRS patients with bilateral disease. The prevalence of high attenuation areas by computed tomography was significantly higher in the AFRS group than in the EMRS group, and the mean Hounsfield unit values of the areas of high attenuation in the AFRS patients were significantly greater than those in the EMRS patients. CONCLUSION AFRS is believed to be an allergic response to colonizing fungi in atopic individuals. In EFRS, local allergies to fungi may play a role in the pathogenesis of the disease. EMRS is thought to be unconnected with fungal allergies.