Suspicious for Malignancy Diagnoses on Pleural Effusion Cytology

Optimal Volume Assessment for Serous Fluid Cytology

OBJECTIVE

This study aimed to investigate the optimal volume of serous fluid needed for accurate diagnosis using The International System for Reporting Serous Fluid Cytopathology (TIS), as well as to provide information on the distribution of serous effusion cases in the TIS categories (ND: non-diagnostic, NFM: negative for malignancy, AUS: atypia of undetermined significance, SFM: suspicious for malignancy, MAL: malignant) and relevant epidemiological data.

METHODS

A retrospective analysis of 2340 serous effusion cases (pleural, peritoneal, and pericardial) from two hospitals between 2018 and 2020 was conducted. TIS categories were assigned to each case, and for 1181 cases, these were correlated with the volume of the analyzed fluid.

RESULTS

Our study found statistically significant differences in volume distributions between certain TIS categories. Statistically lower volumes were observed in NFM compared to MAL, in UNCERTAIN (ND, AUS, SFM) compared to both MAL and NFM, and in NOT MAL (ND, NFM, AUS, SFM) compared to MAL. However, these differences were not substantial enough to hold any clinical relevance.

CONCLUSIONS

This study suggests that while fluid volume may slightly influence the TIS category, it does not impact the diagnostic accuracy of serous effusion cytology. Therefore, the ideal serous effusion specimen volume can be defined solely by practical parameters.

Cytomorphological and immunohistochemical features of pancreatic ductal adenocarcinoma in serous fluids

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) represents the most common primary pancreatic malignancy. An understanding of the cytomorphologic features of conventional ductal adenocarcinoma and its variants is important to ensure accurate diagnoses.

METHODS

The clinicopathological and cytological data of serous fluids in PDAC patients were obtained from the electronic medical records and pathology database. All samples were analyzed and reclassified according to the "The International System for Reporting Serous Fluid Cytopathology" guidelines. Cytomorphologic features were examined with SurePath automatically prepared slides and stained using the Pap method in malignant (MAL) effusion specimens from 21 patients with PDAC. Immunocytochemical staining was conducted on 12 cell blocks from MAL PDAC effusion.

RESULTS

A total of 137 serous fluids specimens of PDACs were included, among which 61 (44.5%), 9 (6.6%), 13 (9.5%), 52 (38.0%), and 2 (1.5%) patients were classified into malignancy, suspicious for malignancy, atypia of undetermined significance, negative for malignancy and nondiagnostic groups, respectively. The key cytologic features for the conventional type of PDAC included cohesive clusters of ductal cells in glandular crowding and disorganized "drunken honeycomb" pattern or intercalated duct-like structure with anisonucleosis, cytoplasmic vacuoles, and concomitant "Indian-file" configuration. Undifferentiated carcinoma was comprised of enlarged, undifferentiated, pleomorphic MAL cells. Adenosquamous carcinoma could show glandular and/or squamous differentiation. Colloid carcinoma was composed of three-dimensional cancer cell clusters floating in thick mucin.

CONCLUSION

Crowding and disorganized "drunken honeycomb" pattern or intercalated duct-like structure with anisonucleosis, may represent an important clue for diagnosing PDAC in serous fluids. Immunocytochemical staining in combination with review of medical records and cytomorphological data can serve as useful adjuncts for distinguishing between PDAC and its variants.

Evaluation of pleural fluid cytology for the diagnosis of malignant pleural effusion: a retrospective cohort study

Background

Cytological examination of pleural fluid has good specificity, but imperfect sensitivity for the diagnosis of malignant pleural effusion (MPE). Published estimates of sensitivity vary and predictors of false negative cytology are not well established.

Aims

To estimate pleural fluid cytology sensitivity and identify risk factors for false negative cytology.

Methods

We conducted a retrospective cohort study of patients who had cytology testing of pleural fluid at Christchurch Hospital, New Zealand, from July 2017 to October 2019. Data on clinical and pleural fluid characteristics were collected. MPE was defined by positive pleural fluid cytology, tissue histology or multidisciplinary meeting consensus. We estimated sensitivity of the first pleural cytology assessment. We performed multivariate logistic regression to ascertain patient groups at greatest risk of false negative results.

Results

Initial pleural fluid cytology was diagnostic in 117 of 156 patients, providing a sensitivity (95% confidence interval (CI)) of 75.0% (67.4–81.6%). The sensitivity was 79.0% (66.8–88.3%) for lung cancer, 91.3% (72.0–98.9%) for breast cancer and 33.3% (95% CI 11.8–61.6%) for mesothelioma. Cloudy appearance of pleural fluid (odds ratio (OR) 0.12; 95% CI 0.03–0.54) and yellow/gold pleural fluid (OR 0.24; 95% CI 0.06–0.96) reduced the odds of false negative pleural cytology. Pleural thickening on computed tomography scan (OR 3.3; 95% CI 1.2–9.4) was a risk factor for false negative cytology.

Conclusion

Sensitivity of pleural fluid cytology was greatest in primary lung and breast cancer, and lowest in mesothelioma. Clinicians should be alert to false negative results when suspecting mesothelioma or if pleural thickening is present.

Application of the International System for Reporting Serous Fluid Cytopathology with Cytohistological Correlation and Risk of Malignancy Assessment

The International System for Reporting Serous Fluid Cytopathology (TIS) classifies serous effusions into five categories: non-diagnostic (ND), negative for malignancy (NFM), atypia of unknown significance (AUS), suspicious for malignancy (SFM) and malignant (MAL). The main objectives of this classification comprise the establishment of a universal code of communication between cytopathologists and clinicians and histopathologists, as well as between different laboratories worldwide, paving the way for the setting of clinical management guidelines based on the risk of malignancy assessment for each diagnostic category. We retrieved the total number of pleural and peritoneal effusion cases of our department for the three-year time period between 2018 and 2020, yielding a total of 528 and 500 cases, respectively. We then proceeded to reclassify each specimen according to TIS guidelines and calculate the risk of malignancy (ROM) for each category by searching each patients’ histology records, medical history and clinical follow-up. For pleural effusions, 3 (0.57%) cases were classified as ND, 430 (81.44%) cases as NFM, 15 (2.84%) as AUS, 15 (2.84%) as SFM and 65 (12.31%) as MAL. ROM amounted to 0%, 5.3%, 33.33%, 93.33% and 100% for each category, respectively. As far as peritoneal effusions are concerned, 6 (1.2%) were categorized as ND with ROM estimated at 16.66%, 347 (69.4%) as NFM (ROM = 9%), 13 (2.6%) as AUS (ROM = 38.46%), 12 (2.4%) as SFM (ROM = 83.33%) and 122 (24.4%) as MAL (ROM = 100%). Our results underline the utility of the current classification, both as a means of communication between doctors of different specialties and as general guidelines for the further clinical management of patients.

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.