Presentation
Signs of raised intracranial pressure
Patient Data
There is a midline lobulated enhancing mass in the posterior cerebral fossa of vermian location with surrounding edema, and mass effect on the 4th ventricle. Dilated 3rd, and lateral ventricles with mild periventricular interstitial edema, indicating obstructive hydrocephalus.
A left schizencephaly is noted (incidental finding).
A ventriculoperitoneal shunt was inserted and an MRI exam was performed 10 days later.
The vermian lesion shows a low signal intensity on T1WI, intermediate to high signal intensity on T2WI and FLAIR with heterogeneous irregular enhancement mainly peripheral with central necrosis, and restricted diffusion on DWI/ADC. Peripheral vasogenic edema with mass effect on the 4th ventricle is noted.
The multivoxel MR spectroscopy shows a dominant peak in Lipids / Lactate (LL), elevated choline and NAA peak at the solid component of a tumor. Depressed metabolites within vasogenic edema around the tumor (not shown).
The tip of the VP shunt is seen in the right occipital horn.
Diffuse thickening with extensive pachymeningeal enhancement most likely due to intracranial hypotension (over-shunting).
Left frontal parenchymal cleft extending from the cortical surface to the lateral ventricle. There is localized area where both sides of the cleft are in contact with no CSF (cleft walls in apposition), lined by abnormal gray matter (polymicrogyria), representing probably closed-lipped variety of schizencephaly. An area of the right frontal cortex appears abnormally thick. The septum pellucidum is absent.
A peripheral enhancing mass with irregular and spiculated borders is seen in the anterior segment of the right upper lobe with associated ipsilateral hilar lymphadenopathy. No parenchymal nodular lesion is seen. Diffuse centrilobular emphysema is noted.
Other CT findings include:
- small calcification in the left lobe of the liver
- multiple and bilateral small renal cysts
- mild peritoneal effusion in the Douglas pouch
- rectal fecaloma
Case Discussion
Radiological features are most consistent with a solitary cerebellar metastasis from lung tumor in a patient with schizencephaly (incidental finding).
A metastasis should always be considered in the differential diagnosis in the presence of a solitary cerebellar lesion in an elderly patient.