Rhino Orbital Mucormycosis in a Kidney Transplant Recipient Despite Initially Negative Sinonasal Imaging

Background: Rhino-orbital mucormycosis is a rapidly progressive opportunistic infection in immunocompromised patients. Early disease may lack characteristic sinonasal findings, which can delay tissue diagnosis. Case Presentation: A 29-year-old man with focal segmental glomerulosclerosis underwent living-donor kidney transplantation in October 2024. He received tacrolimus, mycophenolate mofetil, and corticosteroids. In February 2025, he was admitted with fever, chills, headache, and febrile neutropenia. Initial otorhinolaryngologic examination and paranasal sinus computed tomography showed no findings suggestive of mucormycosis. His prolonged hospital course was complicated by recurrent fever, pancytopenia, and multiple microbiological findings, including Candida krusei, Aspergillus flavus, cytomegalovirus, and adenovirus. When a new crusted lesion developed in the oral cavity and nasal passage, punch biopsy with intraoperative frozen-section assessment demonstrated mucormycosis. Surgical debridement and liposomal amphotericin B at 5 mg/kg/day were initiated, and immunosuppression was reduced. Subsequent contrast-enhanced magnetic resonance imaging demonstrated nasopharyngeal, orbital, and sinonasal involvement. Despite intensive antifungal therapy, surgery, and supportive care, the patient died during hospitalization. Conclusions: Initially normal sinonasal examination and imaging do not exclude mucormycosis in highly immunosuppressed kidney transplant recipients. Repeated examination and urgent tissue sampling are essential when fever persists without a satisfactory response to antimicrobial treatment.