INTRODUCTION

Fungal sinusitis is a relatively common but often misdiagnosed disease process involving the paranasal sinuses. It is a serious condition as certain forms of fungal sinusitis are associated with a high rate of mortality. Successful treatment requires a prompt diagnosis and frequently relies upon radiologic imaging, specifically computed tomography and magnetic resonance imaging.
Fungal sinusitis is broadly categorized as either non-invasive or invasive disease. Non-invasive fungal sinusitis is defined by the absence of hyphae within the mucosal tissue of the paranasal sinuses. Non-invasive fungal sinusitis is subdivided into allergic fungal sinusitis (AFS) and fungus ball or mycetoma. Conversely, invasive fungal sinusitis is defined by the presence of hyphae within the mucosal tissue of the paranasal sinuses. Invasive fungal sinusitis is subdivided into acute invasive fungal sinusitis, chronic invasive fungal sinusitis, and granulomatous invasive fungal sinusitis.

Of the estimated 50,000 species of fungi only a few hundred are known to be pathogenic to humans. Many of these are ubiquitous in our environment. Although many people are colonized by fungi, an intact immune system prevents subsequent infection. Some of the more commonly implicated fungi include Aspergillus, Bipolaris, and Rhizopus