Which characteristics allow us to differentiate PTLD from primary CNS lymphoma?
In PTLD the lesions are predominantly lobar, show ring enhancement and have a heterogeneous appearance. In primary lymphoma, they are commonly periventricular and the enhancement is solid and homogeneous.
What are the differential diagnoses in CNS PTLD?
Glioblastoma, primary CNS lymphoma, metastatic disease and infectious processes.
Multiple (6) intra-axial focal lesions in the subcortical white matter of the frontal lobes bilaterally and at the inferior aspect of the left parietal lobe, predominantly hypointense on T1, heterogeneous signal on T2, with avid ring enhancement after IV gadolinium infusion. The lesion at the left middle frontal gyrus shows punctate T1 hyperintensity, likely reflecting microhemorrhage. In the DWI sequence, there are areas of peripheral diffusion restriction.
Marked perilesional edema, more prominent in the left parietal lobe, with mild effacement of the left lateral ventricle and diffuse effacement of the left convexity sulci.