[The clinical features, neuroimaging findings and pathological characteristics of 26 patients with pathologically proven tumor-like inflammatory demyelinating diseases].

Objective: To summarize the clinical features, neuroimaging findings and pathological characteristics of 26 patients with tumor-like inflammatory demyelinating diseases (TIDD) confirmed by histopathology for better diagnosis and differential diagnosis.

Methods: The clinical features, neuroimaging findings and pathological characteristics of 26 patients (14 male, 12 female) with pathologically proven TIDD (24 brain-type and 2 spinal cord-type) were retrospectively analysed.

Results: The mean onset age was 6 - 69 (36.7 ± 13.8) years. Twenty-one patients had good prognosis with a median followed-up duration of 51.0 months. Two patients were died of post-operative complication and pulmonary infection respectively and the remaining 3 patients were lost to followed up. The TIDD patients almost showed monophasic clinical setting. Headache, indifference accompanied with hypothesis were the commonest initial symptoms. The positive or abnormal rates of cerebrospinal fluid oligoclonal bands (OCB) and myelin basic protein (MBP) in TIDD patients were high. The involvements of bilateral and multi-lesions were commonest in TIDD (61.5%, 65.4% respectively). Twenty-two patients with CT unenhanced scanning showed hypodense lesions. Long T(1) and long T(2) signal intensity was showed on MRI and most cases appeared round-like lesion in shape. According to the shape of enhancement of the 23 patients performed with contrast agents, 11 were shown with open-ring enhancement, 4 cases (including 2 accompanied with open-ring enhancement) with complete ring enhancement, 3 with asymmetrical dotted enhancement, 2 with diffused even enhancement, and no enhancement was seen in the other 6. Furthermore, 14 cases with DWI and 12 with FLAIR all appeared hyperdensity. The typical pathological changes were demyelinating, perivascular inflammatory cells infiltration and reactive gliosis. Occasionally, the Creutzfeldt cells were also found in brain tissue of some patients.

Conclusions: TIDD is a distinct demyelinating disease entity. In spite of being apt to be confused with the neoplasm in brain and spinal cord. TIDD has its own-features, for example, OCB is frequently positive in patients with TIDD and the level of MBP may be significantly increased. Furthermore, the involvements of bilateral and multi-lesions are the common in TIDD, and most cases showed open-ring enhancement or complete rim enhancement on MRI. In addition, all cases present hypodense lesions on unenhanced CT and patients with hyperdense seemed not to be considered as TIDD.