We report an autopsy case of preclinical primary central nervous syste
m (CNS) lymphoma. The case was an 89-year-old female who died of ruptu
re of a thoracic aortic aneurysm. No neurological abnormalities were f
ound throughout our clinical observation. Serum anti-human T-cell leuk
emia virus type 1 and anti-human immunodeficiency virus were negative.
Grossly, the brain was normal except for a small solid tumor, 6 by 6
by 2.5 mm, in the lateral ventricular wall at the left hippocampal fim
bria, and multiple smaller disseminated nodules. Histological examinat
ion revealed multiple microscopic disseminated foci throughout the bra
in, including the cerebral subcortical white matter, basal nucleus, th
alamus, brainstem and cerebellum. Histological classification is of ly
mphoblastic type non-Hodgkin's lymphoma of high-grade malignancy. Lymp
homa cells are positive for leukocyte common antigen and L-26, indicat
ing a B cell phenotype. In situ hybridization with Epstein-Barr viral
probes is negative. It is concluded that this case may represent a rel
atively early preclinical stage of multifocal type of primary CNS lymp
homa.