A 69-year-old man with myelofibrosis presented with a two-day history of left periorbital swelling, blurred vision, and non-radiating dull orbital pain. On examination, there was restricted left-sided extraocular motility with conjunctival injection, chemosis, and periorbital edema. Magnetic resonance imaging demonstrated left-sided pre- and post-septal fat stranding concerning for orbital cellulitis. Two weeks before symptom onset, the patient began fedratinib therapy for myelofibrosis but discontinued this medication upon hospital admission. After restarting fedratinib, he presented with similar right-sided ophthalmic signs. A review of his medication history revealed a temporal relationship between symptom onset and fedratinib use. After medication discontinuation, his symptoms improved rapidly.
Keywords: Drug side effect; JAK2 inhibitor; fedratinib; orbital inflammation.