Miliary Pneumocystis

Figure 1. Granulomatous Pneumocystis

A biopsy of miliary lesions in a patient with chronic lymphocytic leukemia showed this granuloma with fibrosis and central necrosis. Stains for organisms showed no acid fast organisms, but the stain for fungus was positive (see below).

 

Figure 2. Gomori Methenamine Silver (GMS) Stain of Organisms

This organism was recently renamed Pneumocystis jiroveci, in honor of the person who first linked it to human pneumonia.

The GMS stain shows the spore cases. A Giemsa stain would show the trophic forms within the foamy material.

Close examination of the central necrotic region in figure 1 showed a foamy appearance typical of pneumocystis.

For more about pneumocystis see Unknown 14.

Reference

1. Watts J, Chandler F. Evolving concepts of infection by Pneumocystis carinii. Pathol Annu Part 1, 1991; 26:93-138.

Return to Histologic Differential Diagnosis

Rad/Path Home Page