The Differential Diagnosis in Nonlymphoproliferative Malignant Pleural Effusion Cytopathology and Its Correlation with Patients' Demographics.

BACKGROUND: We report our experience with malignant pleural effusion (MPE) and the impact of patients' demographics on the differential diagnosis at the primary site. METHODS: After IRB approval, we searched our pathology database from January 2013 to January 2017 for patients with positive pleural effusions (PEs). Patients' demographics and clinical histories were noted. RESULTS: 474 patients were identified (288 females [61%] and 186 males [39%]), ranging in age from 19 to 64 years old. Ethnicity was distributed as follows: Caucasian (n = 330, 70%), African American (n = 114, 24%) and Asian (n = 30, 6%). The most common primary sites were the lung (n = 180, 37%), followed by the breast (n = 81, 17%), and the gynecologic system (67, 13%). The lung was the most common primary for all ethnicities (n = 190, 40%). The second-most common primary site was the breast in African Americans and Caucasians and upper gastrointestinal (GI) tract in Asians. In 5 cases (1%), the primary tumor could not be determined. CONCLUSION: Cytology examination is a useful method to diagnose primary sites of PE. Pulmonary primary is the most common cause of effusion in all ethnicities. In African American and Caucasian patients, the breast was the second-most common site of MPE, while in Asian patients it was the upper GI tract.

Diagnosing malignant pleural effusions: how do we compare?

INTRODUCTION: Accurate and prompt diagnosis of malignant pleural effusion (MPE) is important as patients with suspected MPE often wait for many days before the diagnosis is secure. AIMS: (1) To evaluate the diagnostic yield of pleural fluid cytology for patients admitted to Middlemore Hospital (MMH) in Auckland, New Zealand with MPE between 31 May 2010-1 June 2011. (2) To document the waiting time for cytology results to be made available and whether this contributed to length of stay. (3) To evaluate whether the volume of pleural fluid analysed contributed to diagnostic yield. METHODS: A retrospective audit of pleural fluid cytology results on 36 consecutive patients admitted to MMH with a pleural effusion which was subsequently proven to be due to malignancy. Data was obtained from hospital medical records and Web Eclair databases. RESULTS: 54.8% (17/31) of patients had positive pleural fluid cytology. Initial pleural fluid cytology was positive in 16 (51.6%). Only 4/15 patients with negative pleural fluid cytology had a repeat aspiration (1 was positive). Median cytology turnaround time was 6.72 days, range 2.23-43.06 days. Average length of stay (ALOS) was 7.78 days, range 1.11-20.8 days. Cytology turnaround times seem shorter for inpatients and when a diagnosis of cancer is unknown but the ALOS is longer if patients have negative initial cytology and when a diagnosis of cancer is uncertain. Samples >50mL appear to have a higher diagnostic yield compared to samples less than and equal to 50mL but this was not statistically significant (77.8% to 41.2%, p=0.08). CONCLUSION: Diagnostic yield from pleural fluid cytology at our hospital is comparable with other documented studies. ALOS appears to be influenced by a negative initial pleural fluid cytology and the uncertainty of diagnosis of cancer, not cytology turnaround time. The results suggest a more efficient diagnostic and treatment algorithm could be considered with emphasis on Day Stay investigation and treatment.