Characterisation of tumefactive demyelinating lesions

Abstract

ObjectivesTumefactive demyelinating lesions (TDLs) occur spontaneously during the course of MS or as the first manifestation of demyelination and may be precipitated by drug withdrawal, vaccination, viral infection or fingolimod. The objective of this study was to identify the frequency, clinical context and radiological features of TDLs in a hospital based cohort.MethodsThis is a retrospective analysis of 515 MS patients from the MS clinic at Royal North Shore Hospital. Lesions were regarded as tumefactive when larger than 2 cm in diameter. Clinical, laboratory and radiological data were collected. The lesions were characterised according to the radiological features and topography and correlated with the clinical presentation.ResultsForty-five (8%) patients had TDLs. More than half of TDLs exhibited ‘ring-like’ enhancement on MRI (58%). A ‘Balo-like’ pattern occurred in 24%. In 71% (32) of patients TDLs developed without a precipitant during the course of MS, and in 27% of patients (12) TDLs appeared in the context of a precipitating factor (prior vaccination, viral infection, treatment with fingolimod or cessation of medication due to pregnancy). In 20 (44%) patients the lesions were exclusive to the WM. The most frequent location of TDLs were the frontal lobes (56%), followed by parietal (53%) and temporal lobes (46%). In six patients TDLs in the cerebellum or brainstem were identified. Patients with multifocal, non-precipitated TDL’s exhibited the highest EDSS (mean 2.44).ConclusionsTumefactive MS is predominantly a white matter disease and lesions are frequently in the frontal lobes and exhibit ring-like enhancement. Curiously, TDLs occur most frequently during the course of otherwise prototypic MS and in this scenario may cause significant disability.

Tumor-like Lesions in Primary Angiitis of the Central Nervous System: The Role of Magnetic Resonance Imaging in Differential Diagnosis

“…The histological correlate of an open-ring enhancement is infiltration by macrophages and angiogenesis at the inflammatory border [ 93 ]. Most TDLs are supratentorial, with frontal lobe (incidence 40.7–56%) and parietal lobe (incidence 42–74.1%) being the most common sites [ 11 , 94 ], followed by corpus callosum, occipital, and temporal lobe. As for PCNSL, the hypoattenuating appearance on NCCT of the areas of enhancement on MRI may be useful to better distinguish TDLs from tumors.…”

“…As previously said, conventional MRI findings (open-ring or incomplete-rim enhancement, a T2 hypointense rim, absent or mild mass effect, and absent or mild perilesional edema) demonstrate variable frequencies [ 94 ]. TDLs can be classified into four different subtypes based on the most prominent conventional MRI characteristics [ 96 ]: megacystic, Balò-like (lesions with multiple concentric/alternating bands of signal intensity), infiltrative (large, ill-defined areas of T2 abnormalities), and ring-like (round lesions with ring-like enhancement).…”