Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 44 3 2015 03 15 374 9 Mehdi Nazeri Dept. of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran. Seyed Jamal Hashemi Dept. of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran. Mohammad Ardehali Amir-alam Hospital, Tehran University of Medical Sciences, Tehran, Iran. Sasan Rezaei Dept. of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran. SeyedMojtaba Seyedmousavi Dept. of Medical Microbiology, Radboudumc, Nijmegen, The Netherlands. Mahdi Zareei Dept. of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran. Emaddodin Hosseinjani Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran. 2015 10 14 Background: Fungal rhino sinusitis (FRS) is an important infection of para nasal sinuses, which encompasses two main categories; invasive and noninvasive forms according to histopathological findings. Aspergillus spp are the most common species isolated from noninvasive form, while Mucorales are more frequently isolates from acute infections. Methods: Four hundred fifty patients suspected to fungal rhino sinusitis were investigated in a cross-sectional prospective study from June 2009 to Sep 2013. All patients under went endoscopic sinus surgery of the middle meatus. Tissue biopsies were investigated for culture, histopathology and molecular examination. Results: Totally, 87 patients were diagnosed with fungal rhinosinusitis. A. flavus was the most common etiological agent of chronic invasive form (CIFRS), allergic fungal rhino sinusitis (AFRS) and fungus ball (FB), while Rhizopus oryze (26.7%) was the most common cause of infection in acute invasive fungal rhino sinusitis (AIFR). However, a few  rare species such as Shyzophyllum commune and Fusarium proliferatum were also isolated. Conclusion: Diabetes is the most important predisposing factor for patients with acute invasive form of sinusitis and the most involved sinuses were unilateral multiple sinuses and maxillary sinus. https://ijph.tums.ac.ir/index.php/ijph/article/view/3640 https://ijph.tums.ac.ir/index.php/ijph/article/download/3640/3315