A 50-year-old woman presents with progressive, painless unilateral proptosis that worsens on the Valsalva manoeuvre and a low, soft compressible mass in the inferomedial orbit. MRI shows a lobulated, well-circumscribed lesion within the orbital fat with high T2 signal and fluid levels. The most likely diagnosis is:
- A Orbital dermoid cyst
- B Capillary hemangioma of the orbit
- C Lacrimal gland pleomorphic adenoma
- D Orbital varix (venous malformation) ✓
Explanation
Orbital varix (venous malformation) is characterised by intermittent or positional proptosis that increases dramatically with the Valsalva manoeuvre, coughing, or dependent head position—because venous blood engorgement expands the malformation. It is a low-flow venous vascular malformation and appears on MRI as a multilobular lesion with phleboliths (calcifications), high T2 signal, and variable enhancement. It may thrombose acutely causing pain. Capillary hemangiomas occur in infants, enlarge with crying, and involute spontaneously; cavernous hemangioma (not varix) is the most common orbital tumor in adults and does not vary with Valsalva.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.