Subacute Onset of Perineural Rhino-Cerebral Mucormycosis Mimicking Giant Cell Arteritis: A Case Report.

A diabetic woman in her 40s presented with a subacute onset of a left temporal headache with no other symptoms, especially no visual or nasal symptoms. An initial diagnosis of giant cell arteritis was made due to a raised erythrocyte sedimentation rate (ESR) and the presence of jaw claudication; however, the temporal artery biopsy was negative. Corticosteroid therapy was commenced, but subsequent computed tomography (CT) imaging of the face revealed extensive left maxillary sinus disease with bony erosion of the greater palatine and vidian nerve canals. The ear, nose, and throat (ENT) examination showed no mucosal necrosis, and initial biopsies were negative for mucormycosis. Given the imaging findings, a tentative diagnosis of mucormycosis was made, and the patient was treated with liposomal amphotericin B. Repeat deep biopsies confirmed the diagnosis of mucormycosis. The nature of the headache was consistent with pterygopalatine neuralgia, given the headache characteristics, taste abnormality, and magnetic resonance imaging (MRI) findings at the pterygopalatine fossa. The importance of the pterygopalatine fossa as a conduit for potential mucormycosis perineural spread is highlighted. This case also underscores mucormycosis as an important mimic of giant cell arteritis, particularly in patients presenting with new-onset unilateral headache and cranial neuropathies.