Case Presentation:

A 71 year-old woman with hypothyroidism and primary biliary cirrhosis presented with one month of progressive memory impairment and confusion. Prior to presentation, she had no memory deficits and was sufficiently managing her activities of daily living. She was up-to-date on routine age-appropriate cancer screening and was not taking any immunosuppressive drugs.

Her neurological exam was significant for 3/5 strength on bilateral shoulder abduction and no other focal deficits. Initial labs were significant for CRP 11, ESR 114, and negative HIV antibody. Brain MRI revealed a curvilinear shaped mass measuring 5cm x 2cm x 2.4cm involving the splenium of the corpus callosum.

She was started on levetiracetam and discharged with plan for biopsy of her brain lesion in 10 days. However, prior to her scheduled biopsy, she was re-admitted for worsening confusion, declining functional status, and falls. She underwent stereotactic biopsy of her brain mass, which revealed a diffuse large B cell lymphoma. There was no evidence of systemic involvement on bone marrow biopsy. She was started on dexamethasone and high-dose methotrexate (MTX) with regression of her brain mass on imaging. Her hospital course was notable for residual confusion, depression, epistaxis, deconditioning, and anorexia. After her second dose of MTX, she and her family decided against further treatment and transitioned to home hospice. She passed away shortly after hospital discharge.

Discussion:

Primary central nervous system lymphoma (PCL) is a type of non-Hodgkin lymphoma affecting the brain, leptomininges, eyes, or spinal cord without evidence of systemic involvement. PCL is a rare disease among immunocompetent patients, with an annual incidence of 5 cases per million persons. Patients with PCL frequently present with neuropsychiatric symptoms including memory impairment, confusion, or depression. After more common causes of altered mental status have been ruled out, it is important to consider a brain lesion and obtain an MRI. While imaging may suggest PCL, a histopathologic specimen is required to make the diagnosis because it is difficult to distinguish PCL from glioblastoma multiforme or metastasis by imaging alone. Stereotactic brain biopsy is the preferred method of obtaining a tissue diagnosis, and it is important to avoid corticosteroids prior to biopsy, as steroids cause tumor cell apoptosis and prevent diagnosis in up to 50% of patients. The best initial treatment for PCL is high-dose MTX. Patients above age 60 and those with a low performance status have the worst prognosis.

Conclusions:

PCL is a rare disease among immunocompetent patients, and it is important to recognize it as a diagnostic possibility in patients presenting with altered mental status. Treatment decisions for elderly patients with PCL must take into consideration their comorbidities and functional status. Palliative care resources should be provided early to patients with PCL and their families.