Case story

A 49 year old white man was admitted after an episode of uncontrolled “twitching” of his left arm and hand that lasted 5–10 minutes. He reported difficulty in finding his words for a few days. Past medical history included three unexplained deep vein thromboses, therefore he was receiving long term warfarin. Clinical examination and limited laboratory tests were unremarkable and he was discharged the same day with no follow up.

In the following days he gradually developed weakness of the right side of his body, headaches, nausea and increasing speech difficulties. He was readmitted four weeks later, after a sustained episode of “twitching” of the right arm, which on this occasion was correctly recognised to be a focal seizure. Systemic features such as malaise, fever or weight loss were absent and recent foreign travel was denied; 4/5 weakness of the right limbs, an expressive dysphasia and apathy were noted but no other psychiatric symptoms were present. Chest radiography was normal. Brain computed tomography showed an area of mixed attenuation in the left posterior frontal region extending into both the temporal and parietal region. There was mass effect with compression of the left anterior horn and slight bowing of the anterior midline structures to the right. These appearances suggested a left frontoparietal malignant tumour, probably a diffuse glioma. He was given carbamazepine 200 mg twice daily and dexamethasone 4 mg four times a day.

Smear examination of a stereotactic brain biopsy from the left frontal lobe, rather than confirming a glioma, revealed a granulomatous inflammatory process and as tuberculosis could not be excluded, triple therapy was started (isoniazid, rifampicin, pyrazinamide) and samples sent for microbiology. Postoperative brain magnetic resonance imaging showed a diffuse swelling with ill defined enhancing abnormality in the left frontoparietal region. The appearances were unusual suggesting a granulomatous …