Case 2

This is an MRI brain study showing a posterior fossa mass with a thin walled larger cystic component attached to a smaller solid nodule; the septated cystic component contains CSF like fluid with high T2 and low T1 signal. The solid component is avidly enhancing on the post gadolinium series, but the cyst wall does not enhance. The mass exhibits surrounding T2 hyperintense signal, representing vasogenic oedema. It exerts mass effect, causing effacement of the right cerebello-pontine angle and 4^th ventricle. 

There is no obstructive hydrocephalus.

The findings are highly characteristic of a haemangioblastoma. The main differential diagnosis is pilocytic astrocytoma. In pilocytic astrocytomas, the solid nodule is often hyperintense to brain parenchyma on T2, which is not the case here. Also, the cyst walls are more likely to enhance in pilocytic astrocytomas.

Another method to differentiate between these two entities is the patient demographic: haemangioblastomas occur in adults, while pilocytic astrocytomas occur mainly in children and adolescents. I would review the age of the patient in this case.

There is an incidentally found mucus retention cyst in the left maxillary sinus.

 I would inform the referring physician of the findings and suggest discussion at neurosurgical MDT. I would also ask if the patient is a known case of Von Hippel Lindau disease, as they are associated with this disease.