A Prospective Study to Evaluate a Diagnostic Algorithm for the Use of Fluid Lymphocyte Subset Analysis in Undiagnosed Unilateral Pleural Effusions

High sensitivity flow cytometry immunophenotyping increases the diagnostic yield of malignant pleural effusions

Diagnosing malignant pleural effusions (MPE) is challenging when patients lack a history of cancer and cytopathology does not detect malignant cells in pleural effusions (PE). We investigated whether a systematic analysis of PE by flow cytometry immunophenotyping (FCI) had any impact on the diagnostic yield of MPE. Over 7 years, 570 samples from patients with clinical suspicion of MPE were submitted for the FCI study. To screen for epithelial malignancies, a 3-color FCI high sensitivity assay was used. The FCI results, qualified as "malignant" (FCI+) or "non-malignant" (FCI-), were compared to integrated definitive diagnosis established by clinicians based on all available information. MPE was finally diagnosed in 182 samples and FCI detected 141/182 (77.5%). Morphology further confirmed FCI findings by cytopathology detection of malignant cells in PE (n = 91) or histopathology (n = 29). Imaging tests and clinical history supported the diagnosis in the remaining samples. The median percentage of malignant cells was 6.5% for lymphoma and 0.23% for MPE secondary to epithelial cell malignancies. FCI identified a significantly lower percentage of EpCAM+ cells in cytopathology-negative MPE than in cytopathology-positive cases (0.02% vs. 1%; p < 0.0001). Interestingly, 29/52 MPE (55.8%) where FCI alerted of the presence of malignant cells were new diagnosis of cancer. Overall, FCI correctly diagnosed 456/522 samples (87.4%) suitable for comparison with cytopathology. These findings show that high sensitivity FCI significantly increases the diagnostic yield of MPE. Early detection of FCI + cases accelerates the diagnostic pathway of unsuspected MPE, thus supporting its implementation in clinical diagnostic work-up as a diagnostic tool.

Primary Effusion Lymphoma-like Lymphoma Mimicking Tuberculous Pleural Effusion: Three Case Reports and a Literature Review

Primary effusion lymphoma-like lymphoma (PEL-LL) is a rare lymphoma, localized in the body cavity without detectable tumor masses. Tuberculous pleural effusion is a form of extra pulmonary tuberculous. We herein report three cases of PEL-LL in patients with a history of pulmonary tuberculosis. Despite the presentation with lymphocyte predominance and high levels of adenosine deaminase, a notable characteristic of tuberculous pleural effusion, the patients were ultimately diagnosed with PEL-LL. Pleural fluid laboratory tests yield similar results for PEL-LL and tuberculous pleural effusion; therefore, cytological and immunophenotyping examinations are useful for their differential diagnosis and the determination of treatment.

Effusion fluid cytology and COVID‐19 infection

Background

Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), which is responsible for coronavirus disease 2019 (COVID‐19), is known to cause severe respiratory infections with occasional accompanying pleural effusion (PE), pericardial effusion (PCE), or peritoneal effusion (PTE). The effect of COVID‐19 on effusion cytology is not yet known. This study aimed to examine the cytomorphologic features and workup of effusion fluids in patients with active COVID‐19 infection versus those in recovery.

Methods

PE (n = 15), PCE (n = 1), and PTE samples (n = 20) from hospitalized patients with a SARS‐CoV‐2 infection (from June 1, 2020, to December 30, 2020) were reviewed. Effusion fluids with metastatic carcinoma were excluded. Differential cell counts, cytomorphology, and relevant immunostains for effusion fluids were retrospectively evaluated and compared between patients with active infection (positive on a SARS‐CoV‐2 nucleic acid amplification test [NAAT] within 2 months; n = 23) and those in the recovery phase from COVID‐19 (negative on a SARS‐CoV‐2 NAAT for >2 months; n = 13).

Results

The cytology diagnoses were negative for malignancy (n = 31), atypical (n = 4), and suspicious for malignancy (n = 1). Active infection cases showed more atypical mesothelial cells than recovery cases (P < .05); some had enlarged nuclei, prominent nucleoli, occasional multinucleation, and bizarre nuclei. Immunostains were performed more often in active infection cases than recovery cases (47.8% vs 7.7%; P < .05). Differential cell counts (available for 28 cases) showed no significant differences between the active infection and recovery groups.

Conclusions

This study found atypical and bizarre mesothelial cells more often in effusions of cases with active COVID‐19 infection in comparison with patients in recovery. It is important for cytopathologists to become familiar with the cytomorphologic effects of SARS‐CoV‐2 on effusion cytology so that these cases can be properly triaged.

This study examined the cytomorphologic features and work‐up of effusion fluids in patients with active COVID‐19 infection versus those in recovery, and found atypical and bizarre mesothelial cells to be present more often in effusions of cases with active COVID‐19 infection than those from patients in recovery. It is important for cytopathologists to become familiar with the cytomorphologic effects of SARS‐CoV‐2 on effusion cytology.

A Simple and Practical Guide for Triaging Lymphocyte-rich Effusions for Ancillary Studies

Lymphocyte-rich effusions of the body cavities may represent a reactive/benign condition, primary effusion lymphoma, or systemic lymphoma with secondary malignant effusion, either as initial presentation or as a late complication. Cytomorphologic examination is essential and fundamental for diagnosis and may provide important clues to the nature of diseases. However, based on morphology alone, cytologic diagnosis of lymphocyte-rich effusions could be very challenging, particularly when the lymphocytes are small. Cytologists/cytopathologists might be uncertain when a lymphocyte-rich effusion specimen warrants a comprehensive hematopathologic workup. Herein we present a simple and practical algorithmic approach. On the basis of the cytomorphology of lymphocytes (small vs. large cells), presence or absence of cellular atypia, and clinical information (an earlier history or current lymphoma), the lymphocyte-rich effusion samples could be triaged for ancillary studies including immunophenotyping and molecular assays if indicated. Incorporation of cytomorphology, correlation with clinical information, and appropriate application of various ancillary techniques is mandatory for a correct diagnosis of lymphocyte-rich effusion specimens.

The Utility of Pleural Fluid Lactate Dehydrogenase to Adenosine Deaminase Ratio in Pleural Tuberculosis

In high-burden settings, the diagnosis of pleural tuberculosis (TB) is frequently inferred in patients who present with lymphocyte predominant exudative effusions and high adenosine deaminase (ADA) levels. Two recent small retrospective studies suggested that the lactate dehydrogenase (LDH)/ADA ratio is significantly lower in TB than in non-TB pleural effusions and that the LDH/ADA ratio may be useful in differentiating pleural TB from other pleural exudates. We compared the pleural LDH/ADA ratios, ADA levels, and lymphocyte predominance of a prospectively collected cohort of patients with proven pleural TB (n = 160) to those with a definitive alternative diagnosis (n = 68). The mean pleural fluid LDH/ADA ratio was lower in patients with pleural TB than alternative diagnoses (6.2 vs. 34.3, p < 0.001). The area under the receiver operating characteristic curve was 0.92 (p < 0.001) for LDH/ADA ratio and 0.88 (p < 0.001) for an ADA ≥40 U/L alone. A ratio of ≤12.5 had the best overall diagnostic efficiency, while a ratio of ≤10 had a specificity of 90% and a positive predictive value of 95%, with a sensitivity of 78%, making it a clinically useful "rule in" value for pleural TB in high incidence settings. When comparing the LDH/ADA ratio to an ADA level ≥40 U/L in the presence of a lymphocyte predominant effusion, the latter performed better. When lymphocyte values are unavailable, our data suggest that the LDH/ADA ratio is valuable in distinguishing TB effusions from other pleural exudates.

Malignant Pleural Effusion: Diagnosis and Management

Symptomatic malignant pleural effusion is a common clinical problem. This condition is associated with very high mortality, with life expectancy ranging from 3 to 12 months. Studies are contributing evidence on an increasing number of therapeutic options (therapeutic thoracentesis, thoracoscopic pleurodesis or thoracic drainage, indwelling pleural catheter, surgery, or a combination of these therapies). Despite the availability of therapies, the management of malignant pleural effusion is challenging and is mainly focused on the relief of symptoms. The therapy to be administered needs to be designed on a case-by-case basis considering patient's preferences, life expectancy, tumour type, presence of a trapped lung, resources available, and experience of the treating team. At present, the management of malignant pleural effusion has evolved towards less invasive approaches based on ambulatory care. This approach spares the patient the discomfort caused by more invasive interventions and reduces the economic burden of the disease. A review was performed of the diagnosis and the different approaches to the management of malignant pleural effusion, with special emphasis on their indications, usefulness, cost-effectiveness, and complications. Further research is needed to shed light on the current matters of controversy and help establish a standardized, more effective management of this clinical problem.

Diagnostic procedure for idiopathic eosinophilic pleural effusion: a single-center experience

Background

Eosinophilic pleural effusion (EPE) is attributed to several well-recognised causes. However, some patients remain idiopathic, even after thorough clinical work-up. The present study aimed to better characterize idiopathic EPE (IEPE) and to outline the diagnostic procedure for this disease.

Methods

Complete clinical data of 11 consecutive patients with IEPE were prospectively collected and analysed. Preliminary diagnostic procedure of IEPE in our hospital was performed.

Results

All the 11 patients had respiratory symptoms and unilateral pleural effusion (PE) occurred in 4 patients. The mean percentage of eosinophils in PE was 22.4% (range, 12.4–50.5%). Lactate dehydrogenase, adenosine deaminase, proteins and carcinoembryonic antigen in PE were 246.0 U/L (range, 89.8–421.9 U/L), 13.8 U/L (range, 1.8–24.0 U/L), 42.6 g/dl (range, 32.8–52.6 g/dl) and 2.17 mg/mL (range, 0.46–4.31 mg/mL), respectively. Parasite-specific IgG antibody in blood and parasite eggs in stool were both negative. No evidence of tuberculosis or malignancy was observed in pleural biopsy. Symptoms and abnormal pulmonary imaging were eliminated after glucocorticoid use.

Conclusions

IEPE is a diagnosis of exclusion. Patients with EPE without a clear cause should be asked to provided complete medical, surgical and drug-related histories. A thorough work-up is essential. Moreover, we recommend follow-up after the use of glucocorticoid until effusion resolves.

Trial registration

GYFYY. Registration No: GYFYY20150901221. Registered time: 1 September 2015. Date of enrolment of the first participant to the trial: 22 January 2016.

Diagnostic value of polymerase chain reaction/acid-fast bacilli in conjunction with computed tomography-guided pleural biopsy in tuberculous pleurisy: A diagnostic accuracy study

Patients with tuberculous pleurisy often remain undiagnosed even after blind thoracentesis and closed pleural biopsy (PB). In this study, we assessed the value of computed tomography (CT)-guided core needle biopsy of pleural lesion and evaluated the diagnostic accuracy of polymerase chain reaction (PCR)/staining for acid-fast bacilli (AFB) in suspicious tuberculous pleurisy undiagnosed in blind thoracentesis.Patients with exudative pleural effusion (PE) without specific etiology after blind thoracentesis and closed PB were enrolled in this study. PB specimens were obtained through CT-guided core needle biopsy of pleural lesion, then underwent PCR, AFB, histopathological examination, and some routine tests. Diagnostic values were evaluated through sensitivity, specificity, negative predictive value, positive predictive value, and accuracy.A total of 261 participants (TB group: 241, non-TB group: 20) were recruited. In this cohort, the sensitivity, specificity, and accuracy were 56.0%, 95.0%, and 59.0%, respectively for PCR, whereas 57.3%, 95.0%, and 60.2%, respectively for AFB. Their parallel test achieved an improved sensitivity (76.8%) and accuracy (77.8%), with a slight decrease in specificity (90.0%). In histopathological examination, granuloma was the most common finding in TB group (88.4%, 213/241), but also observed in non-TB group (10.0%, 2/20). In addition, pleural lymphocyte percentage in TB group was significantly higher than that of non-TB group (92% vs 61%, respectively; P = .003). However, no significant differences were found for other biomarkers.CT-guided core needle PB is essential for patients with exudative PE but undiagnosed after blind thoracentesis. Combining with PCR and AFB, it strongly improves the diagnosis of tuberculous pleurisy.

Chronic follicular pleuritis: a B cell-rich form of nonspecific pleuritis/fibrosis

The parietal pleura is often biopsied in patients with idiopathic pleural effusion, and in up to 40% of cases, a diagnosis of nonspecific pleuritis/fibrosis (NSP) is rendered. The histology of this reaction has not been well described including a pattern of B cell lymphoid hyperplasia described as "chronic follicular pleuritis (CFP)". Thirty-two cases of NSP were studied, of which 13 (41%) corresponded to CFP with the remainder displaying a fibrinous and organizing pleuritis with varying degrees of collagenization. CFP had similar etiologies as NSP with long term follow-up, including cardiac disease, pericarditis, asbestos exposure, and occult malignancy. The importance of recognizing a previously undescribed B cell/plasma cell pleural inflammatory response in reactive pleural disease is discussed.

Investigating unilateral pleural effusions: the role of cytology

The vast majority of undiagnosed unilateral pleural effusions have fluid sent for cytological analysis. Despite widespread use, there is uncertainty about its sensitivity to diagnose malignant pleural effusions (MPEs). Our aim was to ascertain the utility of cytology using a large prospective cohort.Consecutive patients presenting with an undiagnosed unilateral pleural effusion were recruited to this UK-based study. All had pleural fluid sent for cytological analysis. Cytological sensitivity was based on the final diagnosis at 12 months, confirmed by two consultants.Over 8 years, 921 patients were recruited, of which 515 had a MPE. Overall sensitivity of fluid cytology to diagnose malignancy was 46% (95% CI 42-58%). There was variation in sensitivity depending on cancer primary, with mesothelioma (6%) and haematological malignancies (40%) being significantly lower than adenocarcinomas (79%). MPEs secondary to ovarian cancer had high pick-up rates (95%). In asbestos-exposed males with exudative effusions, the risk of MPE was 60%, but cytological sensitivity was 11%.This is the largest prospective study of pleural fluid cytology and informs discussions with patients about the likely requirement for investigations following thoracentesis. In patients presenting with a clinical suspicion of mesothelioma, cytological sensitivity is low, so more definitive investigations could be performed sooner.