A new focal model resembling features of cortical pathology of the progressive forms of multiple sclerosis: Influence of innate immunity.

Multiple sclerosis (MS) is an inflammatory and demyelinating disease of unknown aetiology that causes neurological disabilities in young adults. MS displays different clinical patterns, including recurrent episodes with remission periods ("relapsing-remitting MS" (RRMS)), which can progress over several years to a secondary progressive form (SPMS). However, 10% of patients display persistent progression at the onset of disease ("primary progressive MS" (PPMS)). Currently, no specific therapeutic agents are available for the progressive forms, mainly because the underlying pathogenic mechanisms are not clear and because no animal models have been specifically developed for these forms. The development of MS animal models is required to clarify the pathological mechanisms and to test novel therapeutic agents. In the present work, we overexpressed interleukin 1 beta (IL-1ß) in the cortex to develop an animal model reflecting the main pathological hallmarks of MS. The treated animals presented with neuroinflammation, demyelination, glial activation, and neurodegeneration along with cognitive symptoms and MRI images consistent with MS pathology. We also demonstrated the presence of meningeal inflammation close to cortical lesions, with characteristics similar to those described in MS patients. Systemic pro-inflammatory stimulation caused a flare-up of the cortical lesions and behavioural symptoms, including impairment of working memory and the appearance of anxiety-like symptoms. Our work demonstrated induced cortical lesions, reflecting the main histopathological hallmarks and cognitive impairments characterizing the cortical pathology described in MS patients with progressive forms of the disease.

Restricted diffusion in a ring-enhancing mucoid metastasis with histological confirmation: case report.

We present a case of restricted diffusion in a ring-enhancing cerebellar metastasis in a 58-year-old man. Diffusion imaging showed restriction with low apparent diffusion coefficient values within the cavity. Diagnosis of abscess was suggested based on radiological findings. A suspicious lung nodule was found in the systemic evaluation, and histological examination of the brain lesion confirmed metastatic adenocarcinoma with mucoid content confirmed by further specific pathological tests. We discuss the reason of diffusion findings and the importance of the correct interpretation of this technique in a clinical situation. Our case confirms previous hypothesis about restricted diffusion related to mucoid content in metastasis.