A patient presented with U/L proptosis which was compressible and increases on bending forward. No thrill or bruit was present. MRI shows a retro orbital mass with enhancement. What is the most probable diagnosis?

This patient is suffering from orbital varix. Proptosis that increases on valsalva maneuver or on bending forwards is probably caused by a vascular lesion such as varicosities of the orbital veins. Orbital varices: Primary orbital varices are congenital venous malformations characterized by proliferation of venous elements and massive dilation of one or more orbital veins. Varices within the orbit may have both cystic and solid components. Clinically patients presents with proptosis or globe displacement which increased during Valsalva maneuver. Investigation: CT appearence of the varix is abnormal axial and paicularly coronal sections obtained in a prone position. MRI often shows hyperintense signal on T1 weighted, proton density, and T2 weighted images.