Miliary brain metastases from papillary adenocarcinoma of the lung – unusual MRI pattern with histopathologic correlation

Miliary brain metastases are very rarely described in the literature but if they are, they are quite obvious on magnetic resonance imaging (MRI) and enhance after intravenous administration of the contrast medium. The authors presented a case of miliary metastatic spread to the brain which was invisible on computed tomography and hardly visible on MRI, i.e. as countless, tiny, slightly T1-hyperintense foci that did not enhance. The authors discussed a few T1-hyperintense brain lesions which did not include metastases (except for metastatic melanoma which was a radiological suggestion after brain MRI). Autopsy revealed papillary adenocarcinoma of the lung with numerous metastatic lesions in both cerebral and cerebellar hemispheres and the meninges.