A child presents with unilateral proptosis which is compressible and increases on bending forwards. It is non-pulsalite and has no thrill or bruit. MRI shows retroorbital mass with echogenic shadows. Which of the following is the most probable diagnosis?

The patient in question is presenting with characteristic signs of orbital varix. Proptosis from orbital varix is unilateral (most cases) non pulsalite and has no thrill or bruit. It is compressible and is characteristically precipitated by increasing venous pressure as in assuming a dependent position, (bending forwards). MRI may show echogenic shadows from phebolititis (Venous stasis leads to formation of pheboliths). Ref: Yanojf and Ducker ophthalmology 2nd Edition, Page 731 - 740; Kanski Clinical Ophthalmology 3rd Edition, Page 180 -188.