Solitary brainstem metastasis: comparisons of X-ray computed tomography and magnetic resonance imaging to pathology

A case of solitary brainstem metastasis from a bronchogenic adenocarcinoma is presented. X-ray computed tomography, magnetic resonance imaging, and specimens obtained at autopsy are compared. T2 weighted magnetic resonance images provided evidence for the diagnosis of a diffusely infiltrating process, whereas T1 weighted images demonstrated a clearly defined, well demarcated tumor. Contrast enhanced computed tomography supported evidence obtained from the T1 weighted image. At autopsy, the tumor was a well circumscribed pontine metastasis with surrounding edema. The importance of distinguishing between T1 and T2 weighted images is crucial for establishing a correct diagnosis and for instituting proper therapy. In contrast to some reports, we found that the T2 weighted image was misleading in regard to defining the extent of tumor. We conclude that both images must be considered together to provide an accurate diagnostic estimate.