Atypical presentation of primary central nervous system non-hodgkin lymphoma in immunocompetent young adults

Objective: Primary central nervous system non-Hodgkin lymphoma (PCNSL) is a malignant lymphoma limited to the cranial-spinal axis in the absence of systemic lymphoma. Historically, PCNSL accounts for fewer than 5% of all cases of primary intracranial neoplasms. PCNSL is rare in immunocompetent young adults. Although the prognosis for PCNSL is poor, approximately 20%-30% percent of cases achieve a cure. Methods: We report two cases of PCNSL originating in the ventricle in otherwise healthy immunocompetent young adults. Results: A 27-year-old man presented with 10 days of nausea, vomiting, and headache and was found to have a large intraventricular mass emanating from the choroid plexus with resultant hydrocephalus. He underwent placement of external ventricular drain and systemic and intrathecal chemotherapy for cytologically proven PCNSL. A 31-year-old pregnant woman presented with headaches, vision difficulties, and ataxia and was found to have a septum pellucidum mass. She underwent craniotomy and subtotal resection of the mass with subsequent systemic therapy and whole brain radiation for treatment of PCNSL. Conclusions: To our knowledge, this is the first report of primary CNS lymphoma of the choroid plexus and septum pellucidum in otherwise healthy, immunocompetent young adults.