Looks like either an abscess (caused due to infection) or a tumor like growth at a critical structure of brain called brainstem. The CSF analysis report and plain MRI brain report are not correlating well. This is not very unusual. I would recommend an additional contrast study along with Magnetic Resonance Spectroscopy of the lesion. Additionally a workup for tuberculosis should also be undertaken. I recommend to take a proper neurosurgery consult and follow the neurosurgeon's advise. The patient may require an operative intervention for the lesion +/- a procedure to drain fluid of the brain which is getting accumulated due to obstruction in the fluid pathway by the lesion.