The patient went on to have a needle biopsy/aspiration due to A) the concern for infection and B) the original report suggesting atypical infection as the likely cause. 

Histology

The sections show brain parenchyma with necrosis and mixed inflammation including neutrophils, plasma cells histiocytes and lymphocytes. There are no granulomata. No organisms are seen on H&E section. There is no evidence for malignancy.

PAS, Gram and FITE stain are negative. No acid-fast bacilli (AFB) identified.

Microbiology (on aspirate) 

• Polymorphs ++
• No organisms
• No growth of bacteria, fungi or AFB

Blood cultures negative including aerobic, anaerobic and MGIT.

Mycobacterium PCR: negative.

Peripheral blood: normal white cell count.

Discussion

This is an important case and highlights the importance of not just looking at the dominant lesion, but examining the whole scan for clues and for patterns of involvement. There the distribution is very reminiscent of a M1 occlusion with dominant perforator infarction. Subacute imaging is not common and misinterpretation is common.