Table 1

- Common differential diagnoses of TDL and their main distinguishing laboratory and imaging features.

Para-clinical featureTDLMSPCNSLHGG
MRI T1WIHypointense Open/closed-ringGadolinium enhancing and non-enhancing lesions present2Uniform, contrast-enhancing in 98.9%, often contacting subarachnoid space Solitary in 50-81%3Heterogeneous enhancement4
Gadolinium enhancementMultiple plaquesMay have necrotic areas4
Distinct borders1
MRI T2WIFLAIR: hyper-intense, ≥2 cm lesion (round, infiltrative or cystic)≥1 Ovoid lesion (>3 mm in size), in ≥2 sites of CNS5Usually hypointenseMostly hyper-intense
Hypointense rimPerivenular2Mass effect, perilesional edema4Mass effect, edema4
No/mild mass effect and/or edema1Central vein sign6
Advanced imagingDSC/DWI: heterogeneous ADC values4Reduced amyloid PET activity in black hole areas in T1-weighted MR images9DSC/DWI: Homogenous and lower ADC values than TDL4DSC/DWI: higher ADC and CVB values than PCNSL and TDL4
DSC/ASL perfusion: low CVB1,7Higher CVB than TDLs4,7
FDG/MET-PET: high uptake10
FDG/MET-PET: high uptake10
FDG/MET-PET: No/low uptake8
CSF OCBsPositive in 30%11 – 80%12Positive in 90%2Negative in 90%11Negative11
Cell count42+-+++-
(< 50/mL)
MBP42-/+++-/++-/+-
CSF biomarkers42IL-6 -/+IL-6 -sIL-2R -/+++sIL-2R -
IL-10 -/++IL-10 -
IL-6 -/++IL-6 -

MRI T1WI: Magnetic resonance imaging T1 weighted image, MRI T2WI: Magnetic resonance imaging T2 weighted image, CSF OCBs: Cerebrospinal fluid Oligoclonal bands, TDL: Tumefactive demyelinating lesion, MS: Multiple Sclerosis, PCNSL: Primary Central Nervous system lymphoma, ADC: Apparent diffusion coefficient, CVB: Cerebral blood volume, DSC: Dynamic susceptibility contrast, DWI: Diffusion-weighted imaging, MBP: Myelin basic protein, FLAIR: Fluid attenuated inversion recovery, PET: Positron emission tomography, FDG: Fludeoxyglucose, MET: Metalized Polyethylene Terephthalate, IL: Interleukin