Miliary brain metastases from adenocarcinoma of the lung: MR imaging findings with clinical and post-mortem histopathologic correlation.

Abstract

Miliary dissemination is a rare form of brain metastasis. The clinical and pathologic features of this form are unclear.
We report a 66-year-old man with miliary brain metastases from adenocarcinoma of the lung, describing MRI and neuropathologic findings in the context of previously reported cases.
Initial disorientation progressed to an apallic state within 6 months. Although, CT with administration of contrast agent failed to demonstrate any lesions, MRI with Gd-DTPA administration showed multiple enhancing miliary nodules in the cerebral cortex, basal ganglia, thalamus, cerebellum, and brainstem. Some of those nodules also could be seen on T2-weighted imaging without Gd-DTPA, but were difficult to identify conclusively. A histopathologic examination at autopsy disclosed diffusely distributed miliary tumor nodules in a perivascular distribution without surrounding focal edema or reactive gliosis. Notably, this patient with miliary brain metastases developed disorientation followed by unconsciousness, which overshadowed other focal neurologic signs at that time.
We should consider this pattern of brain dissemination when a cancer is associated with unexplained disturbance of consciousness.