This 62 year old man came to the
emergency room after suffering a first seizure, a tonic-clonic convulsion with
focal onset, witnessed by his wife. He suddenly became quiet, had eye deviation
to the left, and began to twitch in the left face.
He became unresponsive to
verbal commands, and had generalized jerking movements of arms and legs,
lasting for a few minutes. There was a history of carcinoma of the colon, with
recent metastasis to the liver and lung. MR images show a lesion involving the
right second frontal convolution and another in the cerebellum, near the fourth
ventricle, also visible on the sagittal imagemap.
There is contrast enhancement
of the rim of both lesions. Metastatic brain lesions are typically but not
always multiple. The low signal on T2-weighted images of the frontal lesion is
remarkable, since metastases are often associated with high signal. There is
very little surrounding edema or distortion of the frontal cortical
architecture.
In contrast, the cerebellar lesion is quite swollen and displaces
the underlying brainstem, a potentially dangerous situation because of the proximity
of vital brainstem centers involved in regulation of basic functions such as
ventilation. This lesion required prompt attention and careful monitoring.
