Mycology

Question 1

What is the organism and stained visualized here?

Answer 1

Cysts (ascsus) of P. jirovecii in lung tissue, stained with methenamine silver and hematoxylin and eosin (H&E). The walls of the cysts are stained black; the intracystic bodies are not visible with this stain. Cysts are thick walled, rounded, 5-8 uM. Precysts described, 4-7 uM - do not contain intracystic bodies.

Question 2

What is the organism and stain visualized here?

Answer 2

Direct immunofluorescence antibody stain using monoclonal antibodies that target Pneumocystis jirovecii. This image is from a bronchoalveolar lavage (BAL) specimen from a patient with a malignancy.

Question 3

What is the organism below based on life cycle?

Answer 3

P. jirovecii