Primary CNS lymphoma
Loading Stack -
0 images remaining
A large left frontal mass with low T2 signal, vivid contrast enhancement and profound diffusion restriction (ADC ~500 x 10-6 cm2/s) is surrounded by vasogenic oedema which extends across the corpus callosum, with small nodules of enhancement scattered within it.
Features are characteristic of CNS lymphoma.
Patient went on to have surgery.
MICROSCOPIC DESCRIPTION: Paraffin sections show fragments of a densely hypercellular tumour. This is composed of atypical large lymphoid cells with round, oval and angulated nuclei with an open chromatin arrangement, conspicuous nucleoli and a narrow rim of pale cytoplasm.
These show strong membrane immunostaining for CD20, strong perinuclear staining for bcl-2 and strong nuclear staining for MUM-1 and PAX5. These are arranged in diffuse sheets and are admixed with small T lymphocytes (CD4+>CD8+). Frequent mitotic figures are identified.
Similar atypical cells are seen in perivascular spaces in adjacent white matter, extending through vessel walls. The features are of non Hodgkin's diffuse large B cell lymphoma.
FINAL DIAGNOSIS: non-Hodgkin's diffuse large B cell CNS lymphoma