MICROSCOPIC DESCRIPTION: The sections show brain parenchyma in which there is a circumscribed lesion with an epicentre at the interface between cortex and white matter. The lesion is multilocular with locules filled with necrotic inflammatory debris. Dystrophic calcification is also noted. The debris is surrounded by a layer of intensely inflamed granulation tissue. Peripheral to this is a layer of fibrous tissue. Brain parenchyma surrounding the lesion shows intense fibrillary astrocytic gliosis and oedema. Focal acute cerebritis is also noted. Fungal elements with morphology of pesudohyphae, hyphae and yeast forms are identified in Grocott and PAS stained sections. No organisms are identified in Gram stained sections. In particular, no filamentous Nocardia-like organisms are seen. No acid fast organisms are seen in Fite and Ziehl-Neelsen stained sections. The features are of an abscess of likely fungal aetiology. No evidence of tumour is seen.
DIAGNOSIS: "Right frontal subcortical lesion": Abscess of likely fungal aetiology.