Fungal osteomyelitis of the temporal bone and the importance of prompt histopathologic evaluation in diagnosis

Fungal skull-base osteomyelitis of the temporal bone is an extremely rare condition associated with significant morbidity and mortality. Challenges in diagnosis, specifically accurate identification of pathogens, can complicate and delay appropriate treatment. This is a case of an 82-year-old man with a history of chronic kidney disease, prostate cancer, and type 2 diabetes mellitus. He had a history Bell palsy with complete facial paralysis 1 year prior and a 9-month history of worsening otalgia and otorrhea. Noncontrast computed tomography of the temporal bone revealed a well-developed, opacified mastoid with bone erosion in the stylomastoid foramen, mastoid tip, and extending into the temporomandibular joint. Decision for urgent surgical intervention was made. Histopathologic examination of intraoperative frozen section revealed diffuse fungal forms without bacteria or malignancy. Intraoperative specimens were analyzed with Gram stain (no bacteria identified), as well bacterial (aerobic and anaerobic) and fungal cultures, all with no growth. The cornerstone of diagnosis was pathologic visualization of fungus.