Pseudotumoral multiple sclerosis: unveiling its clinical and imaging characteristics

Pseudotumoral Multiple Sclerosis (PTMS) is characterized by lesions larger than two centimeters and/or with a tumefactive appearance, mimicking brain tumors or other space-occupying lesions.

We ought to describe of a cohort of patients diagnosed with PTMS, encompassing detailed imaging analyses, clinical evaluations, and neuropsychological outcomes.

We conducted a retrospective study of patients diagnosed with PTMS according to the 2017 McDonald criteria, followed in a tertiary center between January 2000 and April 2024.

Eighteen patients were included, 15 (83.3%) of whom were female. All patients fulfilled criteria for relapsing-remitting multiple sclerosis (RRMS), with TDL being the initial manifestation in 13 patients. In seven patients, RRMS diagnosis was delayed by a median of 12  months. Sixteen patients exhibited TDL-related neurological symptoms, predominantly motor impairment (n = 15). A total of 27 TDL were detected, presenting as a single lesion in 14 patients (77.8%). Most were supratentorial (n = 20, 74.1%), with infiltrative (n = 11) and ring-like (n = 10) being the most common morphological patterns. Gadolinium enhancement was documented in 13 patients, predominantly exhibiting diffuse/patchy (n = 10) or incomplete ring (n = 7) patterns. Three patients underwent lesion biopsy. The median follow-up period was four years (IQR:1.5-10.4). All patients showed clinical improvement, as corroborated by a reduction in the median EDSS (median = 0.75). Cognitive decline was detected in four patients on last neuropsychological evaluation.

PTMS exhibits substantial clinical and imaging heterogeneity, often requiring a high index of suspicion for accurate diagnosis. Patients showed overall improvement in functional outcomes; however, this should be interpreted with caution given the occurrence of significant iatrogenic morbidity related to brain biopsy and cognitive decline in a subset of patients.