In a diabetic or immunocompromised patient, the earliest sign is not bone destruction but soft tissue beyond the sinus walls — periantral fat stranding, and on MRI a black (non-enhancing) turbinate — then orbital, cavernous sinus and brain extension.
Orient first
- Mucormycosis surged with COVID-19 and steroid use in India; angioinvasion causes necrosis.
- Fungus spreads along vessels through intact bone — so periantral fat changes precede erosion.
- Loss of mucosal enhancement (black turbinate) indicates necrotic tissue for debridement.
Acquire the study
- Non-contrast CT paranasal sinuses 1 mm with coronal reformats; post-contrast for soft tissue extent.
The manoeuvre
- Soft-tissue window: periantral fat stranding (retroantral, pterygopalatine fossa, orbital fat).
- Mucosal thickening that is unilateral and nasal cavity-predominant.
- Bone window: erosion (late sign).
- Orbit: extraconal and intraconal stranding, proptosis.
What confirms it
- Extrasinus spread or non-enhancing mucosa in a high-risk patient; histology and culture confirm.
What licenses you to exclude it
- Normal periantral fat and enhancing mucosa make invasive disease unlikely but do not exclude it early.
The classic misread
- Reassuring because bone is intact.