SCHEDULED DOWNTIME: We will be performing a database migration that will result in the site being unavailable for approximately 1 hour starting at UTC: Monday, 20 May 2024 11:00 PM (check your local time here


Case contributed by Tom Foster
Diagnosis certain


Memory issues, headache, ataxia, weakness, past pointing, dysdiadochokinesis and left sided neglect. Bilateral papilledema. ?Intracerebral mass.

Patient Data

Age: 25 years
Gender: Male

5.4 cm mixed solid/cystic mass within the posterior fossa, obstructing the 4th ventricle with resultant hydrocephalus. Descent of tonsils through the foramen magnum.


Right sided ventricular access device has been placed since the CT scan.

Large left posterior fossa lesion is again seen, mix of solid and cystic components. The cystic components are of high T2/FLAIR signal. The solid components restrict diffusion and demonstrate very mild enhancement.

Case Discussion

Imaging features are consistent with a high grade primary brain tumor. CT of the chest/abdomen/pelvis and MRI spine were also carried out but identified no further findings of significance. 
Differential would include a medulloblastoma or possibly a high grade glioma.

The patient later went on to have the lesion resected and pathology confirmed medulloblastoma:
"Left cerebellar lesion - Classic medulloblastoma WHO Grade 4; SHH activated; no evidence of either MYC or N-MYC amplification"

Medulloblastoma is the most common posterior fossa mass in the pediatric population. It is much less common in adults but should be considered in young adults, especially if imaging features are consistent with medulloblastoma (with the diffusion restriction being a classical finding).

How to use cases

You can use Radiopaedia cases in a variety of ways to help you learn and teach.

Creating your own cases is easy.

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.