Case of the Week
Section Editors: Matylda Machnowska1 and Anvita Pauranik2
1University of Toronto, Toronto, Ontario, Canada
2BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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August 16, 2018
Rhinocerebral Mucormycosis with Perineural Spread Pattern
- Background:
- Invasive fungal rhinosinusitis in immunocompromised patients has a classically reported high (80-90%) mortality. CNS is involved through direct invasion, along perineural spread or through hematogenous spread.
- Relevant Clinical Information:
- Patients are neutropenic or diabetic patients with poor metabolic control. In this case the patient was immunosuppressed due to diabetes and renal transplant.
- Patients are neutropenic or diabetic patients with poor metabolic control. In this case the patient was immunosuppressed due to diabetes and renal transplant.
- Key Diagnostic Features:
- CT: Sinus opacification with bone erosion and adjacent fat/soft tissue stranding. Bone erosion can be subtle (as in this patient’s case) or even absent as angioinvasive fungi may extend along small vessels and vasa nervorum.
- MR can better depict intracranial and intraorbital extension. Fungal sinus secretions can have a low T2 signal. It is the exam of choice for perineural spread, cavernous sinus involvement, meningeal extension, and intraparenchymal abscess.
- Fungal hyphae invade vessel walls and vascular complications such as stenosis, septic thrombosis, or pseudoaneurysm can be seen.
- Differential Diagnoses:
- Complicated non-fungal rhinosinusitis: immunocompetent patients. Bone erosions are less common. They show air-fluid levels and sinusal mucosal enhancement (no evidence of mucosal necrosis).
- Sinonasal squamous cell carcinoma: Solid mass with bone destruction. Can also show perineural spread.
- Sinonasal lymphoma: more solid and homogeneous mass in nasal cavity. Can also be hypointense in T2 and show perineural spread. May be indistinguishable from SCC.
- Wegener's granulomatosis/Granulomatosis with polyangiitis: Bilateral, usually symmetric chronic sinus inflammatory changes and septal perforation. Extra sinusal involvement is seen later in the disease.
- Treatment:
- Prompt diagnosis of invasive fungal sinusitis allows treatment as soon as possible. The outcome may be poor. Treatment consists of aggressive surgical debridement and antifungal therapy.
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