Orbital venous varix - Clinical Tree

Key points

Definition: Orbital venous varix (OVV) is a rare intraorbital vascular malformation composed of single or multiple venous channels that may enlarge intermittently with changes in venous pressure.
Synonym: Orbital venous malformation.
Classic clue: Patients present with enophthalmos or acute intraorbital hemorrhage and are found to have a mass causing painful proptosis aggravated by head down position, coughing, sneezing, or Valsalva maneuver.
OVVs may be primary or secondary.
Primary OVVs are confined to orbit and idiopathic, probably congenital.
Secondary OVVs are acquired secondary to increased blood flow from intracranial arteriovenous malformations (AVMs), carotid cavernous fistula, dural arteriovenous fistula (AVFs), etc., draining into orbit. ^,
Most common cause of intraorbital hemorrhage.
OVVs are rare, accounting for approximately 1.3% of orbital tumors.
Without provocative Valsalva maneuver, they may be difficult to diagnose.
Some venous malformations are nondistensible with the Valsalva maneuver having no effect on size.
May be associated with other intracranial venous anomalies, which may or may not communicate directly with OVV.

Findings depend on multiple factors.
- Whether the lesion is a pure varix alone.
- Whether the venous component is associated with a more complex malformation.
- Whether the varix is or is not clotted. Computed Tomography

These lesions may be found incidentally when computed tomography (CT) is done for other reasons.
CT is not the procedure of choice when magnetic resonance imaging (MRI) can be performed.
Radiation dosages should always be kept in mind when imaging orbits as radiation is clearly cataractogenic.
In today’s radiation-conscious climate, no radiation with MRI is preferable to any radiation dose with CT.
Three-dimensional reconstructions are often useful.

Nonenhanced computed tomogram (NECT):
- High-density mass with occasional phleboliths a characteristic feature.
Contrast-enhanced CT (CECT):
- Performed supine and prone or with the Valsalva maneuver.
- Enhancing mass significantly larger when straining.
- Enhances the same as other venous structures (e.g., cavernous sinus). Magnetic Resonance

Imaging procedure of choice.
Low signal on spin echo sequences in a vascular-shaped structure.
The patient can be imaged supine and then prone to detect significant differences in size of mass as well as degree of exopthalmos.
- Above technique probably preferable to Valsalva and other neck compression techniques.
In the absence of thrombus :
- T1 and T2 are hypointense to extraocular muscles (EOMs).
If thrombus is present :
- T1 heterogeneous with areas of increased signal.
- T2 heterogeneous with areas of increased signal.
Magnetic resonance venogram (MRV) can be used to show extent of abnormal veins.

Good noninvasive modality for orbit.
Multiple dynamic maneuvers including various positions and Valsalva variations are easily performed.
Color Doppler demonstrates flow dynamics.
When patient is upright and at rest, no abnormality may be apparent.
On straining, venous channels dilate and may appear.
Usually appears as a slow flow vascular lesion.

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