STATION 1 ANSWERS

1.    What is the diagnosis?

Brain abscess.

2.    What are the gross morphological features?

The organ shown is the brain. There is a cavity 3 - 4cm in diameter in the left basal ganglia, filled with an ill-defined, soft, brown material which is likely to be pus. The borders of the cavity are lined by a red amorphous material sequestered from the brain white matter and this may be composed of fibrovascular tissue. The surrounding brain parenchyma appears to be swollen, congested and soft. 

3.    What would you expect to see under the microscope?

There is a central region of liquefactive necrosis consisting of a viscous fluid and a fibrous capsule surrounded by reactive gliosis with proliferation of astrocytes and their processes forming a scaffolding around the capsule. 

4.    What are the two causes of death?

a.    Cerebral herniation due to raised intracranial pressure.

b.    Abscess rupture leading to sagittal sinus thrombosis and subsequent brain infarct.

c.    Spread of inflammation to the brainstem. 

Copyright � Joseph Ong 2003