Silent Tumefactive Demyelinating Lesions and Radiologically Isolated Syndrome

Area of Science:

• Neurology
• Neuroimmunology
• Radiology

Background:

• Tumefactive demyelinating lesions (TDLs) are large (≥2 cm) demyelinating lesions in the central nervous system, often presenting with diverse neurological deficits.
• TDLs are rare inflammatory disorders that can mimic brain tumors and may occur in patients with or without multiple sclerosis (MS) or other autoimmune diseases.
• Distinguishing TDLs from neoplasms can be challenging, sometimes necessitating biopsy.

Observation:

• This report presents a unique case of an 18-year-old male with an incidentally discovered asymptomatic TDL on magnetic resonance imaging.
• The patient remained asymptomatic throughout a one-year follow-up period.
• During this follow-up, the patient was diagnosed with radiologically isolated syndrome (RIS).

Findings:

• This is the first reported instance of a tumefactive demyelinating lesion identified within the context of radiologically isolated syndrome.
• The asymptomatic nature and incidental discovery of the TDL challenge previous understandings of its typical presentation.
• The co-occurrence of TDL and RIS suggests a potential, previously unrecognized association.

Implications:

• This case expands the clinical spectrum of TDLs and radiologically isolated syndrome.
• Further investigation into the relationship between TDLs and RIS is warranted.
• Recognizing this association may aid in earlier diagnosis and management of similar future cases, potentially avoiding invasive procedures.