Use of the term atypical cells in the reporting of ascitic fluid cytology: A caveat

Metastatic Voyage of Ovarian Cancer Cells in Ascites with the Assistance of Various Cellular Components

Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy and has a unique metastatic route using ascites, known as the transcoelomic root. However, studies on ascites and contained cellular components have not yet been sufficiently clarified. In this review, we focus on the significance of accumulating ascites, contained EOC cells in the form of spheroids, and interaction with non-malignant host cells. To become resistant against anoikis, EOC cells form spheroids in ascites, where epithelial-to-mesenchymal transition stimulated by transforming growth factor-β can be a key pathway. As spheroids form, EOC cells are also gaining the ability to attach and invade the peritoneum to induce intraperitoneal metastasis, as well as resistance to conventional chemotherapy. Recently, accumulating evidence suggests that EOC spheroids in ascites are composed of not only cancer cells, but also non-malignant cells existing with higher abundance than EOC cells in ascites, including macrophages, mesothelial cells, and lymphocytes. Moreover, hetero-cellular spheroids are demonstrated to form more aggregated spheroids and have higher adhesion ability for the mesothelial layer. To improve the poor prognosis, we need to elucidate the mechanisms of spheroid formation and interactions with non-malignant cells in ascites that are a unique tumor microenvironment for EOC.

Application of the International System for Reporting Serous Fluid Cytopathology (TIS): A Retrospective Institutional Study

BACKGROUND

Cytology of serous effusions is an important diagnostic tool for the diagnosis of cancer, staging and prognosis of the patient. Herein, we retrospectively applied the TIS on reporting serous cytopathology and provided the corresponding risk of malignancy (ROM).

METHODS

Pleural, pericardial and peritoneal effusion samples were retrieved from the archives of our department and reclassified according to the TIS. The ROM for each category was calculated based on available surgical follow-up.

RESULTS

A total 3790 effusions were available for the study. 1292 pleural samples were reclassified: 27 (2.1%) non-diagnostic (ND), 1014 (78.5 %) negative for malignancy (NFM), 86 (6.6 %) atypia of undetermined significance (AUS), 29 (2.3 %) suspicious of malignancy (SFM) and 136 (10.5%) malignant (M). 241 pericardial samples were reclassified: 4 (1.6 %) as ND, 173 (71.8 %) as NFM, 10 (4.1 %) as AUS, 7 (3 %) as SFM, and 47 (19.5%) as M. 2257 peritoneal cases were re-categorized as follows: 31 (1.4 %) as ND, 1897 (84 %) as NFM, 39 (1.7 %) as AUS, 53 (2.4 %) as SFM, and 237 (10.5 %) as M. The ROM was, respectively, for each of the aforementioned categories, 18.5%, 15%, 45.3%, 93%, 100% in pleural effusions, 25%, 13.2%, 35%, 100%, 100% in pericardial effusions and 19.3%, 10.4%, 43.5%, 100%, 100% in peritoneal effusions.

CONCLUSIONS

Pleural, pericardial, and peritoneal cytology show high specificity and moderate sensitivity in the evaluation of serous effusions. The ROM reported in our study was mostly concordant with ROM published by the TIS.

The Indian academy of cytologists guidelines for reporting serous effusion (IACGRSE): An interobserver agreement analysis

Context:

The Indian Academy of Cytologists published Guidelines and categories for Reporting Serous Effusions (IACGRSE) in 2020 to improve consistency and reproducibility of fluid cytology reporting and to guide patient management.

Aims:

To evaluate category-wise agreement while using IACGRSE 2020 categories. To analyze interobserver agreement among participants with different level of training and years of experience.

Settings and Design:

A retrospective interobserver variability study.

Methods and Material:

Study was done with four participants: an expert cytopathologist and three cytopathology fellows with varying experience. Fluid smears from 60 cases with clinical and/or radiological evidence of malignancy were categorized into one of the five IACGRSE 2020 categories. The interpretations of expert cytopathologist were taken as standard.

Statistical Analysis Used:

Interobserver agreement was analyzed using Kappa statistics.

Results:

Previous cases without definitive category got classified into “Atypical cells NOS” (3.33%) and “Atypical cells, Suspicious of Malignancy” (15%). Agreement analysis for IACGRSE 2020 categories showed better concordance for inadequate (I), malignant (V), and benign (II) categories. The range of Kappa for interobserver agreement of fellows was fair to substantial (range 0.1692–0.7249). The participant with substantial diagnostic agreement with expert (κ = 0.729, 88.3%) had the most experience. Causes of major discordance were pertaining to paucity and distribution of cells, and to misinterpretation of reactive mesothelial cells.

Conclusions:

IACGRSE 2020 categories and participants’ experience were important determinants in classifying the effusion fluid cytology smears and interobserver agreement; emphasizing the need to use IACGRSE2020, and sufficient time and training required for accurate diagnosis of fluid specimens.

Categorisation of serous effusions using the International System for Reporting Serous Fluid Cytopathology and assessment of risk of malignancy with diagnostic accuracy

CONTEXT

The International System for Reporting Serous Fluid Cytopathology (ISRSFC) standardises the reporting of serous effusion cytology under five categories: Non-Diagnostic (ND), Negative for Malignancy (NFM), Atypia of Undetermined Significance (AUS), Suspicious for Malignancy (SFM), and Malignant (M). Very few studies have been conducted so far to confirm the risk of malignancy of the different categories.

AIMS

The main objectives of our study were to classify serous effusions according to the ISRSFC categories and assess their risk of malignancy (ROM) and performance parameters.

MATERIALS AND METHODS

All serous effusion samples received from January 2019 to December 2020 were reclassified according to the ISRSFC. Using histopathological diagnosis as the gold standard, ROM and performance parameters were calculated.

RESULTS

A total of 831 pleural effusion samples were reclassified as follows: ND, 3 (0.4%); NFM, 635 (76.4%); AUS, 65 (7.8%); SFM, 60 (7.2%); and M, 68 (8.2%). For 457 peritoneal effusion samples, the reclassifications were ND, 5 (1.1%); NFM, 368 (80.5%); AUS, 19 (4.2%); SFM, 17 (3.7%); and M, 48 (10.5%). All 12 (100%) pericardial effusions belonged to the NFM category. The ROM for the ND, NFM, AUS, SRM, and M categories was 0%, 2.1%, 33.3%, 94.1%, 100%, respectively, in pleural effusions, and 50%, 4.8%, 22.2%, 83.3%, 100%, respectively, in peritoneal effusions. The ROM was 0% for NFM in pericardial effusions.

CONCLUSION

The ISRSFC is an excellent system for accurately classifying serous effusions with greater reproducibility of reports and better communication between pathologist and clinician.

Targeted Sequencing of Ascites and Peritoneal Washing Fluid of Patients With Gastrointestinal Cancers and Their Clinical Applications and Limitations

Cytology from gastrointestinal (GI) cancers is frequently obtained from ascites and peritoneal washing fluids. Examination of ascites and peritoneal washing fluids from patients with GI cancers can help in the tumor staging and prognosis. Tumor-derived DNA in these cytology samples can be a target for next generation sequencing (NGS). Targeted NGS was evaluated in ascites and peritoneal washing samples obtained from 33 patients with GI cancers. These sequences were compared with those from tumor tissue samples, and correlated with cytopathologic findings of the ascites and peritoneal fluid samples. The correlation between fluid and tissue genotyping results was 25%, with a sensitivity of 21.43%. The volume of tumor contained within the fluid samples was low, ranging from ~0 to 10%. Importantly, the sensitivity of detection of somatic mutations in the fluid samples could be increased to 69.2% by assessing samples containing >2% tumor volume. Evaluation of cells from ascitic fluid showed the presence of KRAS, TP53, and CDH1 mutations in 33, 13, and 7%, respectively, of patients with pancreatic cancer, and the presence of KRAS, TP53, and APC mutations in 25, 12, and 13%, respectively, of patients with gastric cancer. Ascites of one of the latter patients acquired KRAS mutation, which was a novel mutation during metastasis. Targeted NGS of ascites and peritoneal washing fluid have clinical implications, as well as limitations, in patients with GI cancers. NGS-based cytology examination may expand cytomolecular practices in GI cancer patients.

Role of CD68 immunohistochemistry in categorizing benign nonmesothelial cell population and refining "atypical" category in serous fluid cytology

BACKGROUND

Body fluids are rich in histiocytes and may mimic atypical epithelial cells morphologically. Histiocytes can pose a significant challenge in serous fluid cytology as they tend to appear atypical due to prolonged accumulation in serous fluids in vivo and processing by liquid-based cytology in vitro. Not many studies have documented the utilization of histiocytic marker such as CD68 in serous fluid cytology, which can subsequently reduce the "atypical" diagnostic category.

METHODS

One thousand one hundred and twenty-nine cases of serous fluid cytology from 2016 to 2019 were reviewed and reclassified based on proposed classification of the international system for reporting serous fluid cytology. There were 133 cases with atypical diagnoses, out of which 51 cases had cellblocks. An immunohistochemistry (IHC) panel, including two mesothelial markers, two epithelial markers, and one histiocytic marker was applied to the atypical samples. Same IHC panel was utilized to evaluate 15 cases each from negative for malignancy (NFM), suspicious for malignancy (SFM), and malignant (MAL) categories for further comparison.

RESULTS

After reevaluation of the cytology material with IHC stains, 924 (82%), 133 (12%), 23 (2%), and 49 (4%) of the cases were reclassified as NFM, atypia of uncertain significance, SFM, and MAL, respectively. Twenty-five out of 51 atypical cases (49%) were downgraded to "benign" after reevaluation with CD68 IHC.

CONCLUSION

Histiocytes can mimic atypical epithelial cells in body fluids. Effective utilization of CD68 IHC will be beneficial in further refining the "atypical" diagnostic category in serous fluid cytology.

Cytohistological correlation in serous effusions using the newly proposed International System for Reporting Serous Fluid Cytopathology: Experience of an oncological center

BACKGROUND

Cytological analysis is part of the initial etiological evaluation of serous effusions. The newly proposed International System for Reporting Serous Fluid Cytopathology (ISRSFC) aims to standardize reporting.

METHODS

All pleural and peritoneal effusion samples admitted for cytological analysis at our institution between 2012 and 2016, and pericardial effusion samples admitted between 2008 and 2018, were reviewed and reclassified according to the ISRSFC. Risk of malignancy (ROM) and performance parameters were calculated.

RESULTS

1496 pleural effusion samples were reclassified: 12(0.8%) non-diagnostic (ND), 944(63.1%) negative for malignancy (NFM), 9(0.6%) atypia of undetermined significance (AUS), 54(3.6%) suspicious of malignancy (SFM) and 477(31.9%) malignant (M). 64 pericardial effusion samples were reclassified: 23(35.9%) NFM, 1(1.6%) AUS, 4(6.3%) SFM and 36(56.2%) M. 763 peritoneal effusion samples were reclassified: 5(0.7%) ND, 457(59.9%) NFM, 12(1.6%) AUS, 37(4.8%) SFM and 252(33%) M. The ROM was, respectively, for each of the aforementioned categories, 57.1%, 23.9%, 50%, 76.2%, 100% in pleural effusions, 100%, 26.3%, 62.5%, 91.7%, 100% in peritoneal effusions and 0% for NFM, 0% for AUS and 100% for M in pericardial effusions. Sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy were, respectively, 61.6%, 100%, 100%, 73.3%, 81.3% for pleural, 100%, 100%, 100%, 100%, 100% for pericardial and 61.2%, 100%, 100%, 70%, 79.7% for peritoneal effusion samples.

CONCLUSION

Serous effusion cytology has a high specificity and positive predictive value and a modest sensitivity and negative predictive value, supporting its role in confirming the diagnosis of malignancy. The ISRSFC will increase standardization and reproducibility in reporting, leading to improved clinical decision-making.