Presentation
Intermittent vomiting x 1 month usually in the morning; however recently the vomiting has been persistent for past 3 days after each meal.
Patient Data
There is a large T2 hyperintense avidly enhancing heterogeneous mass centered within and splaying the fourth ventricle extending downward through the bilateral foramina of Luschka, foramen of Magendie, into the cisterna magna and approximately 1.7 cm below the foramen magnum. The mass exerts mass effect compressing the brainstem most notably at the level of the pons and medulla with mass effect on the proximal cervical spinal cord at C2. The mass also causes superior vermian deviation. Mild punctate calcifications and/or microhemorrhages are within the tumor along with minimal foci of tumoral increased DWI signal.
There is moderate obstructive hydrocephalus with periventricular edema.
No visible associated leptomeningeal metastasis.
Postoperative changes status post suboccipital craniectomy and C1 laminectomy for resection of posterior fossa mass.
Postoperative defect in the posterior fourth ventricle communicating with the foramen magnum.
Linear enhancement along the surgical margins. No abnormal nodular enhancement to suggest residual tumoral disease.
Decreasing hydrocephalus and periventricular edema. Intraventricular pneumocephalus. blood in the right lateral ventricle adjacent to foramen of monro and in the third ventricle. Very small blood/CSF levels in the occipital horns of the lateral ventricles.
Deviation of the septum pellucidum (7 mm) leftward without overall right hemispheric midline shift.
Moderate inflammatory changes in the maxillary sinuses, likely acute maxillary sinusitis.
Case Discussion
Differential diagnoses include: ependymoma, choroid plexus papilloma or carcinoma, medulloblastoma, and atypical teratoid rhabdoid tumor.
Pathology proved to be a posterior fossa ependymoma.
Note: as molecular profiling is unavailable in this case, it would have the diagnosis of posterior fossa ependymoma not otherwise specified (NOS).
Spine MRI was performed to rule out drop mets (images not included): there was no evidence of subarachnoid seeding of tumor.
Tumor was resected as visualized above.