Etiology and characteristics of pseudotumoral lesions and tumefactive demyelination in multiple sclerosis

Cerebral pseudotumoral lesions (CPTL) (>2cm) on magnetic resonance imaging (MRI) may pose a clinical challenge. A majority will occur in the context of multiple sclerosis (MS) - also referred to as tumefactive demyelinating lesions (TDL). The aim of this study was to define and analyze clinical, MRI, and paraclinical data for MS and non-MS patients.

This prospective study included adult patients with CPTL on brain MRI referred to the Neurology Clinic, Belgrade as a tertiary University Center (2019-2023) for clinical workup and treatment. Demographic, clinical, MRI, and paraclinical data were reviewed.

This study included 75 patients, of which 58.7 % had MS. Fourteen patients had previously been diagnosed with MS, while 30 (68.2 %) received the diagnosis of MS in the later course. The concordance of initial and final diagnoses was 52 %. Relapsing disease (p < 0.001) and brainstem presentation (p = 0.039) were significantly more common in MS patients. Headache (p = 0.008) and lethal outcome (p = 0.014) were significantly more common in the non-MS group. Lesions were ring-like more frequently in the MS group (p < 0.001), while patients in the non-MS group frequently displayed infiltrative (p = 0.001) and nonspecific lesions (p = 0.002). The presence of headache and megacystic morphology was associated with the presence of pathology other than MS while the relapsing disease was in favor of MS.

Multiple sclerosis was the most common cause of CPTL. Headache, relapsing course of disease, and megacystic morphology may help discern MS from non-MS pathology. These findings should be challenged in future studies examining larger cohorts.