Primary central nervous system lymphoma
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| ICD-10 | 85.1 |
|---|---|
| ICD-9 | 200.0 202.8 |
Primary CNS lymphoma is a primary intracranial tumor usually present in those with severe immunosuppression --- commonly in those with AIDS --- and represents around 20% of all cases of lymphomas in HIV infection (other types being Burkitt's lymphoma and immunoblastic lymphoma). Primary CNS lymphoma is highly associated with Epstein-Barr virus infection (> 90%) and does not have predilections for any age group. Mean CD4+ count at time of diagnosis is ~50/uL. Because of the severity of immunosuppression at the time of diagnosis, it is to no surprise that prognosis is usually poor.
[edit] Clinical manifestations
Primary CNS lymphoma usually presents with seizures, headache, cranial nerve findings, altered mental status, or other focal neurological deficits typical of a mass effect. Systemic symptoms may include fever, night sweats, or weight loss.
[edit] Diagnosis
MRI or contrast enhanced CT usually shows multiple (1 to 3) 3- to 5-cm ring-enhancing lesions in almost any location, but usually deep in the white matter. The major differential diagnosis is cerebral toxoplasmosis, which is also prevalent in AIDS patients and also presents with a ring-enhanced lesion, although the contrast enhancement is more pronounced in toxoplasmosis and it presents with more lesions.
Because imaging techniques cannot distinguish the two conditions with certainty, patients usually undergo brain biopsy if the lesion is solitary or a trial of toxoplasmosis therapy is non-therapeutic. In the future, it may be possible to use PCR assay of cerebrospinal fluid for EBV DNA.
[edit] Treatment
Surgical resection is usually ineffective because of the depth of the tumor. Treatment with irradiation and corticosteroids often only produces a partial response, but tumor recurs in more than 90% of patients. Median survival is 10 to 18 months in immunocompetent patients, and less in those with AIDS. The addition of IV methotrexate and citrovorum may extend survival to a median of 3.5 years. If radiation is added, median survival may increase beyond 4 years, but at the increased risk of leukoencephalopathy and dementia.
