Rapidly Developing and Elusive Rhino-Orbital-Cerebral Mucormycosis

Purpose: To report a case of rapidly progressing rhino-orbital cerebral mucormycosis that was particularly difficult to diagnose, initially presenting as orbital apex syndrome. Major findings: In this case, a 59-year-old male patient with uncontrolled diabetes presented with a history of facial pain with no ocular involvement. Within 1 day of hospitalization, the patient developed complete ophthalmoplegia and total visual impairment of the right eye. Over the course of 2 hospital stays, several biopsies resulted in no significant histopathological findings, and several cultures resulted in growth of only a single colony of rhizopus mucor from the sinonasal mucosa. Given the high clinical suspicion of an invasive fungal infection, a universal PCR test was performed from a rapidly developing abscess in the frontal lobe and confirmed a diagnosis of mucormycosis. Conclusions: Orbital apex syndrome is a significant diagnosis that can be caused by a variety of factors, including those of fungal, bacterial, neoplastic, or inflammatory origin. Fungal infections, are a particularly concerning cause of orbital apex syndrome, given their ability to penetrate in and through the orbit to the brain, often resulting in an alarmingly high mortality rate. Mucormycosis, specifically rhino-orbital cerebral mucormycosis, is a very severe opportunistic invasive fungal infection, most often afflicting the immunocompromised. A clinician must be very thorough in their workup so as to not miss such a devastating diagnosis. Histopathology and cell cultures are currently the gold standard for diagnosis, with the potential to augment their technical success through the use of molecular techniques, such as universal PCR.