Tumefactive demyelinating disorders as neoplasm mimics: description of a typical case and literature review.

BACKGROUND: Tumefactive demyelinating lesions (TDLs) are a rare form of idiopathic inflammatory demyelinating disease of the central nervous system. The clinical manifestations of TDLs are nonspecific, the initial symptoms are diverse, and the imaging often shows isolated space-occupying lesions, rarely multiple lesions, which are hard to be distinguished with neoplasms.

CASE REPORT: We here report a case of a male adult presented with unilateral limb weakness as the initial symptom, who shows multiple lesions located at the top of the fourth ventricle with typical 'open ring' enhancement characteristics, space-occupying effect and tissue edema, with no central vein sign (CVS). PCT-CT indicated significant hypometabolism in the affected areas. Cerebrospinal fluid oligoclonal bands, both serum and CSF demyelinating antibodies were negative. The final diagnosis of TDLs was confirmed by brain biopsy.

RESULT: After a clear diagnosis and treatment with glucocorticoids, the neurological dysfunction of patient was gradually improved. Two months later, the follow-up cranial MRI showed that the intracranial lesion was significantly smaller than before. One year later, the patient's symptoms do not recur and muscle strength was completely restored.

CONCLUSION: Misdiagnosis between TDLs and neoplastic masses such as brain tumors is common in clinical practice. Timely and accurate diagnosis of TDLs can prevent unnecessary surgical interventions, radiation therapy, and chemotherapy. We expect that this representative case will enhance clinicians understanding of TDLs and improve their ability to diagnose and manage this condition.