58-year-old female with headache. Previous electronic medical records indicate history of metastatic colon cancer. The lateral and third ventricles are stable compared to the prior examination suggestive of mild hydrocephalus. The supratentorial gray-white matter differentiation is preserved. There is no midline shift, intra- or extra-axial fluid collection.Abnormally decreased diffuse attenuation involving the right posterior fossa with extension across midline, demonstrates mild anterior mass effect at the level of the fourth ventricle. This is not significantly changed compared to the previous examination and consistent with patient's known metastatic disease at this level as seen on CT dated 4/24/2009.A new foci of subcentimeter hyperdensity within this area of low-attenuation is new compared to exam dated 6/24/2009, best seen on image 4/30, and may represent focal hemorrhage. Further evaluation with contrast-enhanced MRI or postcontrast CT is recommended.The calvaria and skull base are radiographically normal. The visualized paranasal sinuses and mastoid air cells are normally pneumatized.
Stable posterior fossa diffuse low-attenuation and edema consistent with known metastatic disease now with new focus of high density which may represent focal hemorrhage. Contrast-enhanced MRI or postcontrast CT is recommended for further evaluation as clinically indicated.