A Case Report of Primary Central Nervous System T-Cell Lymphoma Mimicking Autoimmune Encephalitis
Kristi Anderson1, Mazieyar Azad1, Kaleb Culpepper1, Katherine Zarroli2
1UF Health COM - Neurology, 2University of Florida-Jacksonville
Objective:
To describe a rare case of primary central nervous system T-cell lymphoma.
Background:
Primary central nervous system lymphoma (PCNSL) is a rare form of non-Hodgkin lymphoma. Most commonly PCNSLs are found to be diffuse large B-cell lymphoma with only a small percentage having the T-cell phenotype. We present a case of primary CNS T-cell lymphoma mimicking autoimmune encephalitis. 
Design/Methods:
Clinical case report. 
Results:
A 61-year-old woman presented with rapidly deteriorating neuropsychiatric symptoms over 1 month as well as new onset seizures. Continuous EEG captured focal subclinical right temporal seizures, interictal right anterior temporal sharp waves, and diffuse background slowing. MRI brain with and without contrast revealed large subcortical multifocal areas of homogeneous enhancement with nonspecific areas of T2 hyperintense signal throughout the bilateral cerebral hemispheres with areas of cortical extension. Lumbar puncture was notable for a WBC of 3 and protein of 56. CSF ENC2, pdfENS2, and PAVAL panels were negative. Empiric IVIG and steroids were administered for presumed autoimmune encephalitis; no improvement in mentation was noted. Left frontal stereotactic brain lesion biopsy was then performed with results consistent with primary CNS T-cell lymphoma. Patient received whole brain radiation therapy with minimal improvement and ultimately was discharged to hospice care.
Conclusions:

Primary central nervous system lymphomas are rare. Due to the rarity of PCNSL of T-cell origin, the presentation and prognosis can be difficult to evaluate. It is important for clinicians to maintain a broad differential in patients with multicentric areas of enhancement on MRI as these may represent autoimmune related neuroinflammatory disease, but can be a more nefarious pathology of CNS lymphoma. Tissue biopsy should be considered for diagnosis of PCNSL in patients with refractory neurologic symptoms and progressive enhancing lesions on MRI. 

10.1212/WNL.0000000000204292