Evidence for a 'preinvasive' variant of fungal sinusitis: Tissue invasion without angioinvasion.

Clinical experience has suggested the existence of an intermediate form of fungal sinusitis between the categories of non-invasive fungal sinusitis (non-IFS) and invasive fungal sinusitis (IFS). This fungal sinusitis variant demonstrates unhealthy mucosa by endoscopy with fungal invasion, but lacks angioinvasion microscopically, representing what clinically behaves as a 'pre-invasive' subtype of fungal sinusitis. Unlike non-IFS disease, patients with pre-invasive fungal sinusitis were still felt to require anti-fungal medications due to histologic presence of invasive fungus. While sharing some clinical features of IFS, these 'intermediate' patients were successfully spared extended and repeated surgical debridements given the microscopic findings, and have been successfully treated with shorter courses of antifungal therapy. These select patients have had favorable outcomes when managed in a judicious and semi-aggressive manner, in an undefined zone between the treatments for routine fungal ball and aggressive IFS.