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Cytology of treated and minimal Pneumocystis carinii pneumonia and a pitfall of the grocott methenamine silver stain
Author(s) -
Naryshkin Sonya,
Daniels Joan,
Freno Elaine,
Cunningham Larry
Publication year - 1991
Publication title -
diagnostic cytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.417
H-Index - 65
eISSN - 1097-0339
pISSN - 8755-1039
DOI - 10.1002/dc.2840070112
Subject(s) - grocott's methenamine silver stain , pneumocystis carinii , papanicolaou stain , medicine , pathology , stain , pneumonia , cytology , staining , pneumocystis jirovecii , cancer , cervical cancer
To clarify the role of foamy alveolar casts (FACs) in the diagnosis of Pneumocystis carinii pneumonia (PCP), we retrospectively reviewed Papanicolaou (Pap)‐ and Grocott methenamine silver (GMS)‐stained slides from 205 bronchial specimens submitted for suspected opportunistic lung infection. FACs containing sporozoites were seen in 86 cases, all with positive GMS. FACs were absent in 119 cases with negative GMS. In patients previously treated for PCP, Pap showed FAC‐like material which lacked sporozoites. GMS demonstrated clumped degenerated Pneumocystis carinii (PC) cysts. In 17 GMS‐positive cases there were no FACs on Pap due to sampling error and low burden of organisms. Morphologic features of macrophages in these cases can suggest the presence of PC. When FACs are lacking, a special stain is required. When GMS is used, the control must contain PC to avoid a false negative GMS. The inconsistent uptake of GMS by PC is a pitfall which is distinct from sampling error and which to our knowledge has not been previously reported.