Presentation
Previous history of HCC and HCV infection.
Patient Data
Ill-defined hypoattenuation within the left temporal lobe, insular lobe and basal ganglia white matter, as well as involving the splenium of the corpus callosum, non-specific, without evident mass effect or contrast enhancement. MRI should be considered for a better assessment.
Diffuse and ill-defined areas of high T2/FLAIR signal involving the white matter along the left frontotemporal and insular lobes, splenium of the corpus callosum, basal ganglia on the left, and extending inferiorly through the thalamus to the left cerebellar peduncle and mesencephalon. Foci of restricted diffusion are present in those areas and enhancement is irregular and scattered throughout the lesion.
MICROSCOPIC DESCRIPTION: 1-4. Paraffin sections show fragments of brain parenchyma. All of these show varying degrees of infiltration by atypical large mononuclear cells distributed predominantly as single cells between fiber tracts. Large solid aggregates of atypical cells are seen in specimen 4. Infiltration through the walls of several small caliber blood vessels is also seen in specimen 4. There is florid reactive astrocytic gliosis in all specimens. No evidence of demyelination is seen.
Immunohistocheistry shows the atypical large cells to be CD20+, bcl-2+, bcl-6+, MUM1+, CD3-, CD10-, GFAP-, cytokeratin CAM5.2-, CD68-, EBV-. The features are of lymphomatosis cerebri (non Hodgkin's large B cell - non germinal center phenotype)
DIAGNOSIS: 1-4: Brain biopsies: Lymphomatosis cerebri (non Hodgkin's large B cell - non germinal center phenotype)
SUPPLEMENTARY REPORT: About 20% of the tumor cells are c-myc immunostain positive. About 25% of the cells are p53 positive.
Case Discussion
This case illustrates a rare form of primary central nervous system lymphoma (PCNSL).