MICROSCOPIC DESCRIPTION: Paraffin sections of the two specimens submitted for frozen section confirm the presence of numerous tacchyzooites of Toxoplasma and scattered encysted braddyzooites. There are present in a background of extensive necrosis of brain parenchyma which is sharply demarcated from adjacent viable parenchyma. Within the area of necrosis there are ghosts of necrotic blood vessels with peri and paravascular accumulation of neutrophils and chronic inflammatory cells and karryorhectic debris. There is reactive proliferation of small vessels in viable parenchyma. No evidence of tumour is seen. 3. The sections show cerebral cortex and white matter. Within an area of congestion and focal necrosis within deep white matter there are numerous tacchyzoites of Toxoplasma as well as scattered encysted braddyzoites. Scattered encysted braddyzoites are also identified in more superficial white matter and in the cortex. The features are of cerebral toxoplasmosis. No evidence of tumour is seen.
DIAGNOSIS: Cerebral toxoplasmosis