Delayed Development of Mycotic Intra-Cavernous Carotid Pseudoaneurysm after Treatment of Invasive Fungal Sinusitis: A Case Report and Review of Literature

Acute fulminant invasive fungal sinusitis is a rapidly progressing infection of the paranasal sinuses caused by previously colonized fungal spores, most commonly Aspergillus and Mucor species. It is typically seen in immunocompromised patients, such as those with hematologic malignancies, poorly controlled diabetes, or long term steroid use. Any delay in diagnosis and treatment can be rapidly fatal, with mortality rates ranging from 18 to 50%. One recognized cause of mortality is the development and rupture of mycotic carotid aneurysms. Sphenoid sinus involvement is most commonly associated with the development of cavernous carotid aneurysms secondary to its close proximity; however, the incidence of intra-cavernous carotid mycotic aneurysms is still exceedingly rare.

Our patient is a 68-year-old male with sudden idiopathic aplastic anemia and neutropenia, who initially presented with increasing right facial pain. A CT scan showed acute right ethmoid and sphenoid sinusitis. On exam, there were no visual or neurological deficits. Given his immunocompromised state, right endoscopic sinus surgery was immediately performed. Angioinvasive Mucor fungal rhinosinusitis was diagnosed on pathology. Resection was taken to underlying healthy bone, and all tissue exposed was noted to be uninvolved. The patient was initially placed on intravenous amphotericin and caspofungin and transitioned to oral posaconazole on discharge. At 3-month follow-up, the patient had complained of increasing numbness over his right maxillary trigeminal distribution. An MRI revealed a contour abnormality with irregular signal void in the right cavernous portion of the internal carotid artery, suggestive of a developing mycotic pseudoaneurysm. A CT angiography confirmed the diagnosis of a 5 × 6 mm pseudoaneurysm of the right cavernous carotid artery and demonstrated a stenotic segment distal to the pseudoaneurysm. The patient electively underwent successful endovascular coiling of the pseudoaneurysm without neurovascular complications, and is on continued antifungal therapy.

Clinical presentations of invasive fungal rhinosinusitis are variable and may mimic acute bacterial rhinosinusitis; however, visual disturbances, ophthalmoplegia, trigeminal sensory disturbances, and intractable epistaxis may clue in the diagnosis of cavernous sinus syndrome and mycotic aneurysm. Diagnosis requires a high index of suspicion, especially in severely immunocompromised patients. Intracranial carotid mycotic aneurysms carry a significant mortality risk due to their local inflammatory environment and have an unpredictable course in rupture. Mortality rate from rupture has been significantly decreased with the advent of endovascular techniques in combination with parenteral antifungal therapy. The location and friability of intra-cavernous carotid mycotic aneurysms preclude the use of surgical clipping, and selective aneurysmal exclusion is preferred with coil/balloon occlusion or stenting of parent vessel.

We present the diagnosis and management of a patient who developed an intra-cavernous carotid mycotic pseudoaneurysm after initial surgical and medical treatment for invasive Mucor fungal sinusitis. Our aim is to increase the awareness of the possible delayed development of a mycotic aneurysm in patients with previously invasive fungal rhinosinusitis and to review the management options to prevent catastrophic outcomes.

Fig. 1 3-D reconstruction of the mycotic pseudoaneurysm in the cavernous segment of the right carotid artery.

Fig. 2 An axial image of CT angiography demonstrating the right cavernous carotid mycotic pseudoaneurysm.