Dural carcinomatosis: MR demonstration.

A case of pachymeningeal carcinomatosis is presented in which CT evaluation revealed an extraaxial, heterogeneous density over the left cerebral convexity. The finding was believed to be consistent with subdural hematoma, empyema, or meningeal thickening. Magnetic resonance evaluation demonstrated a similar crescentic lesion that was of intermediate signal intensity on both T1- and T2-weighted images. This was thought to be uncharacteristic of either subdural hematoma or empyema. The T2-weighted image showed CSF interposed between the cerebrum and the lesion, limiting the abnormality to the dura or subdural space.