More than 90% of cases can be diagnoses with direct histological examination of tissue, such as sputum, bronchial lavage fluid, exudates and biopsies. Histopathological study with Gomori methenamine silver (GMS) stain or hematoxylin and eosin (H&E) stain revealing large yeast cells with translucent cell walls with multiple buds. In the juvenile form, lung abnormalities are shown in high-resolution CT scans of the lungs, whereas in the chronic form plain X-rays may show interstitial and alveolar infiltrates in the central and lower lung fields. Culture of P. brasiliensis takes between 20–30 days, requiring multiple samples and culture media. Initial culture can occur at room temperature, however after growth is noted, confirmation occurs by incubating at to 36-37 degrees to transform the fungus into yeast cells. Antibody detection is useful both for acute diagnosis and monitoring. Gel immunodiffusion is commonly used in endemic areas, diagnoses 95% of cases with high specificity. Complement fixation allows for a measure of severity of cases by quantifying the antibody level, and is thus useful for monitoring treatment response. It is however only sensitive for 85% of cases, and cross-reacts with H. capsulatum. Differential diagnosis The disease can appear similar to tuberculosis, leukaemia, and lymphoma
Paracoccidioidomycosis
Leukemia
Chromoblastomycosis
Lymphoma
Coccidioidomycosis
Tuberculosis
Conidiobolomycosis
Phaeohyphomycosis