Brainstem syndrome in a man with diabetes receiving haemodialysis

Abstract

The MRI brain (Fig. 1B of Images in Neuroscience: Question) showed abnormal signal extending from the medulla to the midbrain. The area of abnormal signal did not exhibit restricted diffusion on diffusion weighted imaging but did show patchy enhancement following the administration of gadolinium (Fig. 2 of Images in Neuroscience: Question). An examination of the cerebrospinal fluid (CSF) revealed a normal opening pressure, a normal white cell count and protein level. However, CSF protein electrophoresis demonstrated intrathecal synthesis of immunoglobulin G (IgG). Cytological analysis of the CSF did not reveal any malignant cells. A whole body [18-F] fluorodeoxyglucose–positron emission tomography (FDG–PET) scan did not demonstrate any metabolically active lesions outside the brainstem. The patient was initially treated with a combination of antibiotics to cover the possibility of a listeria rhombencephalitis, anti-fungals, anti-tuberculosis medication and dexamethasone. The patient remained stable initially but a sudden neurological deterioration prompted a stereotactic biopsy at the level of the pons. The biopsy revealed a large diffuse B-cell lymphoma as the cause of the patient’s neurological presentation (Supplementary Fig. 1 of Images in Neuroscience: Question). The neoplastic cells expressed CD20, BCL2 and BCL6 and were negative for CD10 and CD3. The Ki-67 labelling index was approximately 90%. A CT scan of the patient’s chest, abdomen and pelvis did not reveal any lymphadenopathy or underlying malignancy. In view of the normal FDG–PET