Presentation
Headache and left sided ataxia.
Patient Data
There is a 11 mm acute left medullary hemorrhage. This is a solitary finding, with no further brain parenchymal abnormality.
This is an unusual site for a hypertensive hemorrhage, and other etiologies such as underlying vascular malformations, in particular a cavernoma, or underlying mass should be considered.This has been discussed with the treating team, with MRI recommended.
Enhancing lesion identified centered over the inferior aspect of the fourth ventricle and posterior aspect of the medulla. Susceptibility correlates to the high-density material identified on CT which may be a combination of calcium and/or hemorrhage. The ventricular size remains age-appropriate. MRA (not shown) demonstrates no focal vascular abnormality. Several FLAIR hyperintense foci are identified within the deep white matter most in keeping with small vessels in the changes. No other focal lesions identified.
Conclusion:
Mass lesion centered overlying the inferior aspect of the fourth ventricle causing mass effect on the poster aspect of the medulla has features most in keeping up with a tumor. With these appearances and in this location, ependymoma would be the most likely diagnosis.
Case Discussion
The patient went on to have surgery.
Histology:
Paraffin sections show a moderately hypercellular ependymoma. Tumor cells have mildly pleomorphic round and oval nuclei with a pepper and salt chromatin arrangement and are arranged in well-formed peri-vascular pseudo-rosettes. An occasional ependymal canal is identified. Scattered mitotic figures are identified. No vascular endothelial cell hyperplasia is seen and there is no necrosis. No evidence of invasion into brain parenchyma is seen. Focal calcification is noted.
FINAL DIAGNOSIS: posterior fossa ependymoma. WHO Grade 2
Note: as molecular profiling was not carried out in this case, it would have the diagnosis of posterior fossa ependymoma not otherwise specified (NOS).