Rhino-Sino-Cerebral Mucormycosis Associated with Long-Term Rituximab Therapy in Multiple Sclerosis: A Case Report and Review of the Literature

Introduction: Rituximab is a CD20 depleting agent, widely used as an off-label diseasemodifying treatment (DMT) in treating multiple sclerosis (MS). The present study aimed to report the first case of rhino-sino-cerebral mucormycosis in a patient with secondary progressive MS (SPMS), treated with rituximab. Case Report: The patient was a 38-year-old man with a history of SPMS treated with rituximab, who developed subacute left vision loss and impaired ocular movement. He also mentioned a concomitant severe headache and cheek swelling. Based on the brain and orbital magnetic resonance imaging (MRI) findings, rhino-sino-cerebral mucormycosis was suspected. Subsequent endoscopic examination confirmed the diagnosis. He underwent medical treatment with amphotericin B liposomal and surgical debridement leading to a significant clinical recovery. He was eventually discharged home with a solid recommendation to discontinue rituximab. Conclusion: The present report indicates a case of SPMS treated with rituximab, who developed rhino-sino-cerebral mucormycosis.