Atypical Posterior Reversible Encephalopathy Syndrome in Intraorbital Lymphoma after Tumor Biopsy: An Illustrative Case.

A 63-year-old male presented with visual loss and left eye proptosis. Magnetic resonance imaging revealed a left orbital tumor, measuring 1.4 cm × 0.9 cm. The patient underwent left frontotemporal craniotomy to perform a biopsy of the tumor. During the postoperative period, the patient developed the first episode of a generalized tonic-clonic seizure.  Computed tomography of the brain showed hypodensity of the bilateral basal ganglia and thalami with associated edematous white matter hypodensity of bilateral temporo-occipital lobes compatible with atypical posterior reversible encephalopathy syndrome (PRES). The patient received antiepileptic medication and was observed for clinical seizure. One week later, computed tomography of the brain showed the reversible process of PRES. The pathology report revealed diffuse large B cell lymphoma. Following pathological diagnosis, the patient received treatment with whole-brain radiotherapy.  This is the first reported case of atypical PRES associated with orbital lymphoma following craniotomy for the purpose of tumor biopsy. Early detection as well as seizure and blood pressure control, is essential for the proper treatment of PRES.