Abstract Details

Title Tumefactive Lesions as Debut of Multiple Sclerosis

Topic Multiple Sclerosis

Presentation(s) P11 - Poster Session 11 (11:45 AM-12:45 PM)

Poster/Presentation
Number 20-007

Objective The aim of this study is to describe the demographic, clinical, and radiological characteristics of patients whose first MS manifestation was associated with tumefactive demyelinating lesions (TDLs) in a Latin American cohort.

Background TDLs are large plaques (≥ 2 cm) characterized by mass effect, perilesional edema, and contrast enhancement. Although uncommon, reported in only 1.4–8.2% of multiple sclerosis (MS) cases, they pose a significant diagnostic challenge due to their radiological resemblance to tumors, abscesses, or inflammatory encephalitis.

Design/Methods

A retrospective study was conducted including patients diagnosed with MS who were evaluated at a tertiary referral center in Argentina between 2006 and 2025 . Clinical records,brain and spinal MRI scans and laboratory data were reviewed; cases with incomplete information were excluded.The following parameters were collected: sex, age at diagnosis, initial clinical manifestations, number and location of TDLs, presence and pattern of contrast enhancement on MRI, and cerebrospinal fluid oligoclonal bands (OCBs).

Results Among 1,228 patients diagnosed with MS according to prevailing criteria, 30 (2.44%) presented TDLs as their first manifestation. Women represented 63% of the cohort, and the median age at onset was 26.5 years (IQR 19.25–35). Clinically, 67% of patients presented multifocal manifestations, with atypical symptoms such as encephalopathy (17%) and seizures (3%) being notable. On MRI, only 10% of patients exhibited a solitary TDL, with supratentorial localization being the most frequent. Contrast enhancement was present in 66% of cases, most commonly showing an incomplete ring pattern. OCBs were positive in 67% of patients

Conclusions TDLs are an infrequent presentation of MS, it is associated with atypical clinical features and imagenological findings that can impede correct diagnosis

Authors/Disclosures
Ana P. Sieben Samek, Jr., MD PRESENTER	Miss Sieben Samek has nothing to disclose.
Cecilia Pita	Cecilia Pita has nothing to disclose.
Ricardo Alonso	Ricardo Alonso has nothing to disclose.

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