Pericardial fluid cytology: An analysis of 128 specimens over a 6‐year period

BACKGROUND: Pericardial fluid (PF) accumulates through various mechanisms and cytology is part of the workup to determine the specific etiology, primarily to rule in or rule out malignancy. To the best of the authors' knowledge, the current study is the largest systematic evaluation of PF cytology performed to date. METHODS: PF specimens collected over 6 years were retrieved. Clinical history, laboratory, cytologic, and pericardial biopsy results were recorded. RESULTS: A total of 128 PF specimens were obtained from 113 patients (56 males and 57 females), representing 4.5% of all fluids. Of these, 95 cases (74.2%) were benign, 2 (1.6%) had "severely atypical cells, " and 31 cases (24.2%) were malignant. The most common etiologies for benign PF specimens were neoplasm (23.1%), idiopathic (19%), infection (14.7%), and connective tissue disease (12.6%). The most common neoplasm producing malignant PF was lung carcinoma, both in males (75%) and females (52.2%), with adenocarcinoma being the most common type (72.2%). In females, breast carcinoma was the second most common neoplasm (39.1%). Approximately 87.1% of patients with malignant PF specimens had a prior history of malignancy and approximately 32.7% underwent a concomitant pericardial biopsy. The false-negative rate for cytology was 14.7% (hematologic malignancies 2 cases, metastatic sarcoma 1 case, and sarcoidosis 1 case not detected) and that for pericardial biopsy was 40% (metastatic carcinoma 4 cases not detected). CONCLUSIONS: PF specimens are uncommon. A specific interpretation is rendered in approximately 98.4% of cases. Lung carcinoma is the most common tumor to produce malignant PF in both males and females. Approximately 87.1% of patients with malignant PF have a known history of malignancy. Although cytology is superior to pericardial biopsy in diagnosing metastatic carcinoma, other tumors may go undetected in the PF.