Primary Central Nervous System Lymphoma Presenting as Isolated Multiple Cranial Neuropathies: An Extremely Rare Case.

Primary central nervous system lymphoma (PCNSL) is an uncommon malignancy of B-cell origin that typically involves the brain, eyes, and spinal cord without systemic spread. PCNSL typically involves the cerebral hemispheres, basal ganglia, or periventricular region. Isolated leptomeningeal PCNSL without any evidence of parenchymal involvement is very rare. We present a very unusual case of PCNSL presenting as persistent bilateral Bell's palsy and trigeminal neuralgia with magnetic resonance imaging (MRI) brain showing significantly hypertrophied enhancing bilateral facial and trigeminal nerves.