A Case of CNS Lymphoma Imitating Post-Vaccination ADEM (P14-13.003)

Abstract

<h3>Objective:</h3> NA <h3>Background:</h3> A previously healthy 42-year-old male presented acutely with slurred speech, confusion and urinary incontinence several weeks after receiving a COVID booster and Tdap vaccination. <h3>Design/Methods:</h3> NA <h3>Results:</h3> Initial workup revealed multifocal enhancing T2 white matter hyperintensities in the bilateral frontal/parietal lobes, corpus callosum and bilateral midbrain, sparing the cerebellum and spinal cord. Contrast enhanced CT of the chest, abdomen and pelvis showed no masses or lymphadenopathy. Cerebrospinal fluid analysis showed a mild lymphocytic pleocytosis (12) with normal RBC, protein, glucose, negative meningitis/encephalitis PCR, cytology and autoimmune encephalitis antibodies. Serum testing was negative for HIV, RPR, NMO, MOG and antinuclear antibodies. Working diagnosis of acute disseminated encephalomyelitis was made and he was started on IV methylprednisolone 1g daily for 5 days followed by an oral steroid taper with a weekslong improvement in symptoms to his neurologic baseline followed by relapse. We repeated MRI brain which demonstrated mixed response to treatment and two repeat CSF analyses showed 2 WBC with negative cytology. Given symptom recurrence, 1g daily IV methylprednisolone was re-administered for 5 days with another brief improvement, followed by IVIG 2g/kg over 5 days. Despite aggressive immunotherapy, his symptoms continued to worsen, and he was referred for brain biopsy confirming the diagnosis of primary diffuse large B-cell lymphoma of the CNS. At the direction of neuro-oncology, the patient underwent 6 cycles of systemic high-dose methotrexate and rituximab and 2 cycles of temozolomide with PET/MRI evidence of complete response (no lesion enhancement). His performance status improved significantly, and he underwent autologous hematopoietic stem cell transplant for consolidative therapy. <h3>Conclusions:</h3> CNS lymphoma should be considered in the differential for contrast-enhancing FLAIR hyperintensities and can be steroid responsive. Brain biopsy should not be delayed in cases where CNS lymphoma is a leading differential as it can guide early disease management and help improve patient outcomes. <b>Disclosure:</b> Dr. Frank has nothing to disclose. Dr. Alalami has nothing to disclose. An immediate family member of Dr. Livingston has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Sanofi. An immediate family member of Dr. Livingston has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Sanofi. The institution of an immediate family member of Dr. Livingston has received research support from Vertex. The institution of an immediate family member of Dr. Livingston has received research support from Roche. The institution of an immediate family member of Dr. Livingston has received research support from AstraZeneca. The institution of an immediate family member of Dr. Livingston has received research support from Enanta. Dr. Hu has nothing to disclose. Dr. Shadbehr has nothing to disclose.