Cavernous haemangioma of the orbit
One-liner
Most common benign orbital tumour in adults. Painless progressive proptosis, intraconal, well-encapsulated, progressive "fill-in" enhancement.
Key facts
- Peak 20-40 years, female predominance
- Intraconal (within muscle cone), usually lateral to optic nerve
- Well-encapsulated with pseudocapsule (surgically friendly)
- Histology: large endothelium-lined vascular channels separated by fibrous septa, slow flow, no significant arterial feeder
Nomenclature
WHO 2018 reclassified as "cavernous venous malformation" (slow-flow venous malformation, not true neoplasm). Examiners may use either term.
Imaging
CT
- Well-defined oval/round intraconal mass
- Phleboliths virtually pathognomonic (uncommon in orbit though)
- Smooth bony remodelling, no destruction
MRI
- T1: iso-to-low signal
- T2: markedly hyperintense (stagnant blood in large vascular spaces)
- Enhancement: progressive centripetal "fill-in" (same behaviour as liver haemangioma)
Ultrasound
- Well-defined, high internal reflectivity, low flow on Doppler
Differential diagnosis
| Diagnosis | Location | Key distinguishing feature |
|---|---|---|
| Schwannoma | Intraconal | More heterogeneous, no fill-in enhancement |
| Optic nerve meningioma | Intraconal | Avid uniform enhancement, dural tail, calcification, encases nerve |
| Lymphoma | Extraconal/diffuse | Moulds around structures rather than displacing |
| Dermoid cyst | Extraconal (commonly superolateral) | Fat content, well-defined, younger age |
| Lacrimal gland tumour | Extraconal (superolateral) | Lacrimal fossa location, bony changes |
Board pearls
- Intraconal mass + middle-aged female + fill-in enhancement = cavernous haemangioma
- Displaces optic nerve, does not encase it (encasement = meningioma or lymphoma)
