Posterior Fossa and Skull Base Tumors — WACS Viva & Clinical Scenarios (Neuro-Oncology and Skull Base Disorders)

Exam-style posterior fossa and skull base tumors viva scenarios with examiner probes and model answers for Neurosurgery candidates.

Scenarios covered

• SCENARIO 1: A 6-year-old child presents to the emergency surgical unit with a 4-week history of morning headaches, projectile vomiting, progressive truncal ataxia, and bilateral papilledema. Brain MRI demonstrates a midline fourth ventricular, contrast-enhancing, hyperdense mass arising from the vermis with secondary triventricular obstructive hydrocephalus.
• SCENARIO 2: A 42-year-old woman presents with progressive right-sided sensorineural hearing loss over 18 months, episodic vertigo, and recent onset of right facial numbness and mild gait unsteadiness. MRI of the brain with gadolinium shows a 3.2 cm heterogeneously enhancing mass centered at the right cerebellopontine angle with widening of the internal acoustic meatus and compression of the pons and middle cerebellar peduncle.
• SCENARIO 3: A 35-year-old man presents with progressive occipital headache, dysmetria, and intention tremor of the left upper limb. Neurological examination reveals left-sided cerebellar signs. Complete blood count reveals a hematocrit of 58%. MRI of the brain reveals a cystic cerebellar lesion with an intensely enhancing mural nodule abutting the pial surface.
• SCENARIO 4: A 28-year-old woman presents with progressive exertional suboccipital headaches exacerbated by coughing and Valsalva maneuvers, accompanied by numbness in both hands and burning dysesthesias across her shoulders. Sagittal T1 and T2 MRI demonstrates cerebellar tonsillar herniation 8 mm below the foramen magnum associated with a cervicothoracic syrinx (C2–T4) without evidence of hydrocephalus or bony basilar invagination.
• SCENARIO 5: A 7-year-old boy undergoes uneventful gross total resection of a large midline ependymoma of the fourth ventricle. On postoperative day 2, the nursing staff reports that the patient has stopped speaking, demonstrates severe emotional lability, poor trunk control, and exhibits pooling of secretions with an absent gag reflex.