Diagnosis and categorization of malignant effusions: A 6-year review from a single academic institution

Pericardial effusion cytology: malignancy rates, patterns of metastasis, comparison with pericardial window, and genomic correlates

INTRODUCTION

Cytologic evaluation of pericardial fluid is essential for diagnosing malignant pericardial effusions secondary to metastatic disease and for guiding appropriate clinical management; however, large cohort and up-to-date studies on malignancy rates and distribution of primary tumor sites is lacking.

MATERIALS AND METHODS

A retrospective analysis of pericardial fluid specimens from 2 large academic medical centers over a 10-year period was conducted. Clinical and specimen characteristics were correlated with cytologic diagnoses, and compared with surgical pathology pericardial specimens when available. In addition, genomic testing results were examined in a subset of malignant cases.

RESULTS

A total of 1667 pericardial fluid specimens were evaluated, with 15.3% diagnosed as malignant. Lung cancer (50.6%) was by far the most common primary tumor causing malignant pericardial effusions, followed by breast (13.0%), hematolymphoid (12.6%), and gastrointestinal (6.1%) cancers. A subset of patients with paired cytology and surgical pathology pericardial specimens showed concordance in 84.2% of cases, with discordant cases more frequently presenting with a positive cytology but negative surgical pathology result. Genomic analysis of a subset of malignant pericardial effusions revealed the most frequently mutated genes to be TP53, KRAS, CDKN2A/B, and PIK3CA, with a larger proportion of high tumor mutational burden (≥10 muts/Mb) in pericardial fluid samples compared to primary or metastatic sites.

CONCLUSIONS

While lung cancer is the most frequent cause of a cytology-confirmed malignant pericardial effusion, familiarity with relative frequencies of metastases from other sites can be particularly helpful, especially in the diagnostic work-up of an occult malignant pericardial effusion.

Research progress and treatment status of malignant ascites

Malignant ascites (MA), a common and serious complication of various cancers in the abdominal cavity, originates from the extensive infiltration, metastasis, and growth of cancer cells in or on the abdominal cavity, leading to abnormal accumulation of fluid in the abdominal cavity and the formation of MA. MA seriously reduces the quality of life of cancer patients, shortens their survival period, and generally has a poor prognosis. Modern medicine has developed various strategies for the treatment of MA, including targeted supportive treatment, diuretic treatment, abdominal paracentesis, surgical intervention, and intraperitoneal administration therapy. Among them, chemotherapy, as one of the important treatment methods, includes both systemic chemotherapy and intraperitoneal chemotherapy, especially pressurized intraperitoneal aerosol chemotherapy (PIPAC), hyperthermic intraperitoneal chemotherapy (HIPEC), and foam-based intraperitoneal chemotherapy (FBIC), providing a new choice for the treatment of MA. In addition, innovative treatment methods such as gas-based intra-abdominal hyperthermia (GIH) combined with dehydration therapy have also shown promising application prospects. This article delves into multiple aspects of MA, including its concept, mechanism of occurrence, clinical manifestations, differential diagnostic methods, and current treatment status and research progress. This comprehensive review aims to provide valuable references for effectively controlling MA, improving cancer patients' quality of life, and prolonging the survival cycle of cancer patients in clinical practice. Malignant ascites (MA) is a common complication of cancer, which originates from the extensive infiltration, metastasis, and growth of cancer cells in the abdominal cavity or peritoneum, leading to abnormal accumulation of peritoneal fluid. It is a common clinical manifestation in the late stage of cancer. Its symptoms are stubborn and recurrent, which can lead to abdominal pain, bloating, poor appetite, fatigue, breathing difficulties, and even multiple organ failure. The median survival time for cancer patients with MA is generally 5 to 6 months. The prognosis is poor, and it is imperative to seek more active and effective treatment plans. This article reviews the research and treatment status of MA, aiming to provide certain value for controlling MA and improving the quality of life of patients.

Role of Immunocytochemistry in the Cytological Diagnosis of Mesothelioma

BACKGROUND

Mesothelioma is an aggressive malignancy of the serosal surfaces with very poor prognosis. It traditionally manifests in older patients and at an advanced stage which results in minimal improvement in prognosis despite the recent advances in management. Early detection would therefore significantly impact management and potentially improve survival. Mesothelioma frequently presents with recurrent effusions, posing cytology as the initial procedure in the workup. A definitive diagnosis would not only spare the patients additional diagnostic procedures but also potentially afford them an opportunity for early surgical intervention and therapy.

SUMMARY

In this article, we review the role of immunocytochemistry (ICC) in the workup of mesothelioma. The various ICC markers to confirm or rule out mesothelial lineage are reviewed. In addition, newly introduced molecular surrogates that confirm the malignant nature of the mesothelial cells and support a definitive diagnosis of mesothelioma are discussed. We also briefly discuss the theranostic implications of such markers and potential impact of such recent advances on the cytological diagnosis and reporting of mesothelioma.

KEY MESSAGES

The cytological diagnosis of mesothelioma no longer requires the extensive expertise in morphological analysis and can be offered based on supporting ICC that confirms the mesothelial lineage and malignant nature of the cells.

Comparative genomic and immunopathologic analysis of lung adenocarcinomas with and without cytology-proven malignant pleural effusions

BACKGROUND

Lung cancer complicated by malignant pleural effusions (MPEs) is associated with significantly increased morbidity and mortality, yet the mechanisms of MPE development remain poorly understood. This study sought to elucidate whether there were specific genomic alterations and/or immunologic biomarkers associated with the presence of MPEs.

METHODS

Analysis of comprehensive genomic and immunologic profiling for 275 locally advanced (stage III) or advanced (stage IV) lung adenocarcinomas was subcategorized into cytology-confirmed MPE-positive (MPE+; n = 139 stage IV) and MPE-negative (MPE-; n = 30 stage III + n = 106 stage IV) groups.

RESULTS

Smoking frequency (p = .0001) and tumor mutational burden (p < .001) were demonstrated to be lower in the MPE+ group compared to the MPE- group. Median overall survival in the MPE+ group was shorter than in the MPE- group across all data (2.0 vs. 5.5 years; p < .0001) and for smokers (1.2 vs. 6.4 years; p < .0001). There were a number of differences at the genomic level across all cases and when stratifying by smoking status, including a higher frequency of EGFR mutations and a lower frequency of STK11 mutations in the MPE+ cohort. Finally, investigation of the comutational profiles of tumors by MPE status revealed differences in TP53- and STK11-mutant tumors between the two groups.

CONCLUSIONS

Overall, these findings imply that there are both clinical and genetic factors associated with advanced lung adenocarcinoma MPEs. Future studies of these alterations may prove important both for understanding the pathophysiology of MPE development in advanced cancer and for the earlier detection of at-risk patients.

Risk factors for early readmission to hospital in patients with malignancy-related ascites: a retrospective cohort study

Introduction

Malignancy-related ascites (MRA) is a common serious complication of many advanced malignant tumors with high morbidity and mortality. The high hospital expenditures induced by unplanned readmission in patients with MRA have become an urgent issue to the public. We aimed to overall assess the unplanned early readmission rate of patients with MRA and explore the potential risk factors for such readmission.

Methods

A retrospective cohort study based on 2018 Nationwide Readmissions Database was performed and patients with MRA were recruited into the analysis. The primary outcome was unplanned 30-day readmission rate and inpatient outcomes. The multivariate logistic regression analysis was performed to evaluate the potential risk factors for such early readmission.

Results

Data obtained from 32,457 patients with MRA were analyzed, and of these 7,799 individuals (24.03%) were unplanned readmitted within 30-day follow-up. The mortality rate in the readmitted population was 15.15%. Patients at younger age were at a higher risk of readmission. The morbidities including hypertension (OR=1.117, 95%CI: 1.054-1.184), hyperlipemia (OR=1.075, 95%CI: 1.009-1.146) and diabetes (OR=1.118, 95%CI: 1.053-1.188), gastrointestinal malignancies and peritoneal procedure significantly increased the risk of 30-day readmission in patients with MRA.

Discussion

More than one in five patients with MRA was unplanned readmitted within 30-day follow-up. The above risk factors should be timely intervened and the corresponding medical care should be strengthened in patients with MRA to lessen the unplanned readmission and improve the readmission outcomes.

Metastatic germ cell tumors in serous cavities and cerebrospinal fluid: A single-center experience

BACKGROUND

Metastatic germ cell tumors (GCTs) involving body cavity effusions and cerebrospinal fluid (CSF) are rare. Diagnosis is challenging because of limited morphological and clinicopathological information in the literature.

METHODS

A database search of our institution from 1990 to 2024 identified 27 cases of metastatic GCTs, comprising five pediatric and 22 adolescent and adult patients, in serous cavities or the CSF, including peritoneal (15), pleural (nine), CSF (two), and pericardial (one) fluid.

RESULTS

The most common primary site was the testis (n = 10), followed by the ovaries (n = 7), mediastinum (n = 4), retroperitoneum (n = 3), pineal gland (n = 2), and sacrum/coccyx (n = 1). The primary tumors in 14 patients were mixed GCTs (six with a seminoma component), followed by immature teratomas (six), yolk sac tumors (three), embryonal carcinomas (two), pure seminomas (one), and postpubertal teratomas (one). The median interval between primary tumor diagnosis and diagnosis of fluid positivity was 7 months (range: 0-134 months). In nine cases, the malignant fluid was diagnosed simultaneously with or within 1 month of the primary tumor. GCT subtyping was performed on 23 of the 27 cytological specimens. Twenty-four patients (89%) also had metastases to other sites. Thirteen patients died of the disease (48%), with a median survival time of 4 months.

CONCLUSIONS

Metastatic GCTs in serous effusions and CSF are often associated with disseminated disease and poor prognosis. Subtyping can be performed by cytomorphology combined with immunohistochemistry.

Optimal fluid volume for detecting malignancy in serous effusions: a single institution experience

INTRODUCTION

Detection of malignant cells in serous fluids is an indicator of advanced stage of malignancy and is critical in clinical management decisions and prompt treatment initiation. The minimum volume which is ideal for detecting malignancy in serous fluid is not well established. In this study, we aim to identify optimal volume that will be ideal for adequate cytopathological diagnosis.

MATERIALS AND METHODS

A total of 1597 samples of serous fluids from 1134 patients were included in the study. Samples were diagnosed based on International System for Reporting Serous Fluid Cytopathology (ISRSFC). Clinicopathologic results from different diagnostic groups were compared and statistically analyzed.

RESULTS

Pleural fluids comprised 890 (55.7%) specimens, followed by 456 (28.6%) peritoneal, 128 (8%) ascites, and 123 (7.7%) pericardial fluid specimens. The majority were negative for malignancy (1138, 71.3%), followed by malignant (376, 23.5%), atypical (59, 3.7%), and suspicious for malignancy (24, 1.5%). Malignancy was identified in sample with volumes from 5 mL to 5000 mL. Rate of detection of malignant cells increased significantly with higher sample volumes. For malignancy detection the optimal volume for overall serous fluid is 70 mL. Pericardial fluid is an exception, with lower mean volume and significantly lower proportion of cases with malignant diagnosis.

CONCLUSIONS

Our study indicates that higher fluid volumes have a higher rate of malignancy detection and a low false-negative rate. We recommend a minimum of 70 mL of serous fluid for optimal cytopathologic examination and malignancy detection. Pericardial fluid is an exception, with lower mean volume and thus lower requirement.

Effusion cytology of metastatic carcinosarcoma

Objectives

Carcinosarcomas (CSs) are rare gynecological neoplasms seen in elderly females. These are composed of malignant epithelial and mesenchymal components, which appear as adenocarcinoma and high-grade sarcoma. Effusions are encountered uncommonly in CS.

Material and Methods

The study focuses on the cytomorphology of 10 cases of metastatic CS in effusions. In 6 years, there were 10 (0.45%) cases of metastatic CS in effusion samples out of 2240 malignant effusion samples. The samples were processed by SurePath™ and centrifuge technique. Both May-Grünwald-Giemsa and Papanicolaou stained smears were evaluated for cytomorphological features, and the findings were correlated with subsequent histopathology.

Results

The cells were predominantly arranged in ball-like clusters and discretely. The cells had abundant vacuolated cytoplasm and enlarged pleomorphic nuclei. Occasional cases showed scattered spindle cells. The cases were diagnosed as metastatic adenocarcinoma (7/10) and positive for malignant cells (3/10). None of the cases was diagnosed as CS. The primary of these cases was in the uterus (7/10) and ovary (3/10).

Conclusion

The cytological evaluation of such effusion samples rarely demonstrates the classical biphasic pattern of these tumors. Mostly, the carcinomatous component is evident, and the sarcomatous element is inapparent and readily missed.

Serous cavity metastasis: Evaluation of unknown primary

Malignant effusions can occur in patients with neoplasia. Once a metastatic diagnosis is confirmed, the primary site of origin of malignancy needs to be ascertained. This task can be challenging without a prior history of malignancy. In some patients their effusion may be the initial presentation of an underlying malignancy. Metastases usually present with a dual population of mesothelial and malignant cells. Combining cytomorphologic examination with ancillary testing such as immunocytochemistry can help identify the origin of the foreign malignant cell population. Helpful architectural clues include a single cell pattern, solid cell ball pattern, single file arrangement, papillary formation, psammoma bodies and background mucin. Useful cellular features include the presence of signet ring cells, small cells, pleomorphic and multinucleated giant cells, squamous cells, spindle cells and pigmentation. Rarely, despite an extensive work-up the primary site of origin for a malignant effusion may remain unresolved. This review article will be incorporated finally as one of the chapters in CMAS (CytoJournal Monograph/Atlas Series) #2. It is modified slightly from the chapter by the initial authors in the first edition of Cytopathologic Diagnosis of Serous Fluids.

A retrospective analysis of pleural effusion specimens based on the newly proposed International System for Reporting Serous Fluid Cytopathology

BACKGROUND

Recently, the International System for Reporting Serous Fluid Cytopathology (TIS) has been established, with an aim to standardize reporting and guide clinical decision making.

METHODS

The cytological and clinicopathological data of pleural effusions were retrieved from the pathology database and electronic medical records. All specimens were evaluated and reclassified in accordance with the TIS recommendations. Finally, the risk of malignancy (ROM) and performance parameters were measured.

RESULTS

A total of 2454 pleural effusion specimens were included, among which 30 (1.2%), 1670 (68.1%), 151 (6.2%), 54 (2.2%) and 549 (22.4%) patients were classified into non-diagnostic (ND), negative for malignancy (NFM), atypia of undetermined significance (AUS), suspicious for malignancy (SFM) and malignancy (MAL) groups, respectively. The most commonly diagnosed malignancies were lung cancer (48.4%), ovary cancer (10.2%), breast cancer (7.5%), and 21.3% unknown primary site (UPS). Among the 36 UPS patients, the most common site of origin was lung (36.1%), followed by ovary (13.9%) and breast (11.1%) via immunocytochemistry of cell block. The calculated ROM values were 26.7%, 12%, 62.3%, 77.8% and 100% for ND, NFM, AUS, SFM and MAL groups, respectively. When considering MAL as the only positive group, the diagnostic accuracy, sensitivity, specificity, positive and negative predictive values were determined to be 95.2%, 81.9%, 100%, 100% and 93.6%, respectively.

CONCLUSION

The newly proposed TIS is an easy-to-master, user-friendly, and standardized classification system, especially when applying on pleural effusions. An adequate serous sample, application of immunocytochemistry, review of cytomorphological data and past medical history could enhance the accuracy of cytological diagnosis.

Serous fluid cytopathology: Past, present, and future

Serous fluids/effusions are common cytology samples that reflect a wide range of diseases and lend themselves to a multitude of investigations that include microscopy, chemical analysis, cell count, cultures, and analysis for biomarkers and immunomarkers. In recent years, effusions have also served as a liquid biopsy that can be interrogated by molecular tests for thoranostic and prognostic markers and selection of targeted therapy. The recently published International Reporting System for Serous Fluid Cytopathology (IRSSF) provides a standardized reporting terminology with well- defined diagnostic criteria. This editorial provides a global review of the progress in the work-up of effusions and a summary of the IRSSF book and its most significant contributions. The editorial also includes a summary of the diagnostic categories including their definition and the significant relevant information.