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.