Unusual Presentation of Orbital Cellulitis as an Inflammatory Pseudotumor in a Kidney Transplant Recipient.

We reported the unusual presentation of a 62-year-old kidney transplant recipient with acute unilateral eye swelling and fever suggestive of severe orbital cellulitis with features of a space-occupying inflammatory lesion of the orbit. The clinical course deteriorated despite the therapy with broad-spectrum antibiotics alone. The computed tomography scan findings were significant for moderate thickening of the right superior rectus muscle and asymmetric enlargement of the superior ophthalmic vein. These features brought an orbital pseudotumor, or nonspecific orbital inflammation, to the differential diagnoses. With multidisciplinary team management including internal medicine, infectious disease, ophthalmology, and transplant nephrology, the patient's condition improved with immunosuppressive therapy adjustment, intravenous glucocorticoids followed by a steroid taper, and aggressive antimicrobial therapy. Immunocompromised patients can have atypical and severe presentations of infection with rapid progression. Prompt diagnostic workup and urgent computed tomography scan or magnetic resonance imaging scan of the orbits to assess the extent of inflammation, including abscess formation or intracranial extension, are crucial. Judicious antimicrobial coverage, as well as careful immunosuppression adjustment to ensure the best outcome, is often required.