Answer
The most typical presentation of PCNSL in an immunocompetent patient is progressive focal symptoms indicative of a mass lesion. Seizures may occur. Sometimes, nonspecific mental status change leads to the diagnosis. Several variant presentations of PCNSL are discussed in this section.
Patients with AIDS are more likely to present with an encephalopathy than other patients with PCNSL. This correlates with the more often multifocal, diffuse enhancement pattern seen on magnetic resonance imaging (MRI) scans. A history of concurrent infections is quite common, and the median CD4+ count is 20 cells/µL.
Much of the history taking should be devoted to establishing whether the patient may have immune deficiency. A careful sexual and drug abuse history is necessary. If the patient is a transplant recipient, the nature and duration of immune suppression must be clarified.
The diagnosis of PCNSL in immunocompetent and immunocompromised patients is particularly difficult if they present with one of the variant syndromes outlined here.
Isolated, ocular, or meningeal tumor may occur in the absence of any focal abnormalities on MRI. Such patients give a history of (1) blurred vision, (2) headache, (3) isolated cranial nerve dysfunction (eg, diplopia, dizziness, dysphagia, facial numbness, monocular visual loss), or (4) spinal nerve root symptoms (eg, pain, dysfunction localized to 1 dermatome, bowel or bladder problems).
Relapsing, remitting lesions may disappear for periods of as long as several months to a year or more. Administration of corticosteroids may cause prolonged remission of clinical and radiographic signs and symptoms, but remission also occurs spontaneously.
Progressive dementia or stupor with no focal signs and with little or no enhancement on MRI may be more common in patients with AIDS who have PCNSL.
Intravascular malignant lymphomatosis (previously called neoplastic angioendotheliosis) is a series of strokelike focal events, and the MRI may look like multiple large- and small-vessel ischemic strokes and at times single or multiple focal intracerebral hemorrhage. Parasitosis, malignant lymphoma, or metastatic brain tumor often enter the differential diagnosis. Diagnosis often moves away from stroke by the steady progressive clinical course and is often confirmed by brain biopsy and histology and immunochemical staining of the biopsy specimen.
Neurolymphomatosis is the only PCNSL syndrome that involves both the central and peripheral nervous systems at presentation. Cerebral lymphoma with focal mass lesions, as well as infiltration of peripheral nerves, is seen.
