《Slide 44.》Pneumocystis carinii pneumonia & Cytomegalovirus (CMV) pneumonitis,  Lung

A. Brief Descriptions：

1. Pnumocystis carinii pneumonia:

(1) Cup-shaped or boat-shaped cysts (4~6 mm).

(2) Diffuse or patchy pneumonia.

(3) The affected lung are airless, red and beefy.

1. CMV pneumonitis: interstitial pneumonitis.

B. Gross Findings：

1. PCP : Airless, red, or beefy lung.

C. Micro Findings：

    Pneumocystis carinii pneumonia

• HE: the alveolar spaces filled by an amphophilic, foamy, amorphous material resembling proteinaceous edema fluid composed of proliferating parasites & cell debris.

• Toluidine blue: trophozoites.

• Methenamine-silver: typical cup-shaped cyst with trophozoites in the cyst.

    Cytomegalovirus (CMV) pneumonitis

• Interstitial pneumonitis by the characteristic intranuclear inclusion body surrounded by a clear halo in the enlarged alveolar lining cells, endothelial cells of septal capillaries & alveolar macrophages.

D. Others:

Pneumocystis carinii pneumonia

1. Opportunistic infection of pnemocystis carinii, measuring up to 6 um, usually concurrent infection by opportunistic bacteria, fungi, viruses especially CMV.

Cytomegalovirus (CMV) pneumonitis

1. Opportunistic infection in debilitated or immunocompromised patient, e.g. AIDS.

E. Reference：

1. Robbins Pathologic Basis of Disease, 6^th ed.  P.376,381-382.

　

 

【 Fig. 44-1 (LP)】A high proportion of alveolar space is filled with pinkish substance, so the airspace is obliterated, and the architecture of lung is hard to identified at a glance.

　

 

 

【 Fig. 44-2 (LP)】The non-involved alveoli show emphysematous change.

　

　

 

【 Fig. 44-3 (HP)】The alveolar space is filled with foamy amorphous material ( right, upper and lower). A CMV-infected enlarged epithelial cell with typical bull-eye appearance with large intranuclear inclusion body surrounded by a clear halo.

　

 

 

【 Fig. 44-4 (HP, silver stain)】The cup-shaped Pneumocystis carinii organisms within a sputum sample.