FROM THE ARCHIVES OF THE AFIP - PRIMARY CENTRAL-NERVOUS-SYSTEM LYMPHOMA - RADIOLOGIC-PATHOLOGICAL CORRELATION

Once an extremely rare neoplasm, primary lymphoma of the central nervo us system (CNS) now ranks behind only meningiomas and low-grade astroc ytomas in prevalence. Understanding of primary CNS lymphoma has increa sed greatly in recent pears as a result of special immunohistochemical stains. Virtually all primary CNS lymphomas are composed of B cells. Although a viral cause has been suggested in some cases, the exact cau se of the disease is still under investigation. Primary CNS lymphoma h as a distinct affinity for perivascular extension. Although granular n odules may be seen at gross pathologic inspection, diffuse microscopic spread is always present, which accounts for the ability of this tumo r to produce distant disease and local recurrences. The dense cellular ity of the tumor and its predilection for the periventricular region a lso explains its typical hyperattenuated appearance on unenhanced comp uted tomographic scans and hypointensity on T2-weighted magnetic reson ance images. Virtually all lesions enhance with contrast material. Alt hough the overall prognosis for patients with primary CNS lymphoma rem ains poor, some advances have been made with radiation therapy and che motherapy for this once uniformly fatal disease.