Secondary pericardial malignancies: a critical appraisal of the role of cytology, pericardial biopsy, and DNA ploidy analysis.

The authors studied 112 pericardial fluids (45 malignant, and 67 benign) from 63 men and 33 women. All cytologic (n = 112) and histologic (n = 61) specimens were reviewed. Statistical analysis was conducted in 61 paired cytology and histology specimens (45 malignant and 16 benign) and correlated with available ploidy analysis of fluid specimens (n = 34). In cases of malignancy (41 patients), the primary site was known in 34 patients, whereas no origin for metastatic disease was apparent in 3 patients. Pericardial cytology yielded the initial diagnosis in four patients. After careful review of all cytology and histology specimens, seven truly discrepant cases were noted, six of which had positive cytology. Tissue biopsy sampling error was the cause for such discrepancies. DNA diploidy obtained by flow cytometry correlated with benign cytology, whereas aneuploidy was associated with malignant cytology in a total of 32 of 34 cases (94%). Cytologically malignant effusions rendered diploid DNA in 2 of 10 cases (20%). In conclusion, cytology is the single most important parameter in the evaluation of secondary pericardial malignancy and should be considered the gold standard. Causes for false-negative cytologic diagnoses include scant cellularity and obscuring blood. Hence, careful screening is recommended. The low sensitivity of flow cytometric DNA analysis does not favor its routine use.