Invasive Fungal Sinusitis in an Immunocompetent Patient After Sinus Surgery for Chronic Rhinosinusitis with Nasal Polyps and a Mycetoma.

Acute invasive fungal sinusitis (AIFS) classically presents as an aggressive fungal infection that can spread beyond its origin in the sinuses in immunocompromised patients. Although there have been reports of AIFS in immunocompetent, non-diabetic patients, it is extremely rare and the true mechanism behind it is unknown. A thirty-eight year old immunocompetent, non-diabetic woman underwent bilateral ESS for chronic rhinosinusitis with nasal polyps at a tertiary care center and post-operatively developed AIFS. Patient underwent uncomplicated ESS, was packed with foam containing triamcinolone and discharged on steroid rinses and a prednisone taper. Surgical pathology demonstrated left-sided colonization with non-invasive fungal elements consistent with a mycetoma. She presented on post-operative Day 11 with headache and left-sided retro-orbital pain. A culture of her left nasal cavity grew Rhizopus spp and MRI demonstrated evidence of invasive fungal infection of left sphenoid mucosa as well as inflammatory changes in the left orbit centered at the orbital apex. She was started on amphotericin and underwent a left-sided debridement with biopsies which demonstrated angioinvasive fungal disease. Her vision in her left eye worsened to 20/800 and she was treated with transcutaneous retrobulbar injection of amphotericin B. After stable interval imaging she was discharged on a long-term course of antifungals. Extensive immunologic work-up was unremarkable. We describe a case of an immunocompetent patient who developed AIFS after sinus surgery for CRS and a mycetoma likely as a result of local immune suppression and post-surgical trauma. Laryngoscope, 2024.