Cytological Diagnosis Of Malignant Mesothelioma Research Articles

Cytological Diagnosis of Malignant Mesothelioma: A Case Series.

Background:Mesotheliomas are neoplasms of the serosal lining of the body cavities. Diagnosis requires a multimodal approach of clinical findings, cytology, and histopathology with immunohistochemistry (IHC). The published sensitivity of cytology for diagnosing mesothelioma ranges from 30% to 75%.Aim and Objectives:This study aimed to calculate the incidence of malignant mesothelioma (MM) at our institute and to study the cytological features of MM.Materials and Methods:A retrospective study of pleural, peritoneal, and pericardial fluids submitted at our institute was done. The duration of the study was 8 years (2011–2019). Apart from examining Giemsa smears, a panel of immunocytochemical (ICC) and cell block immunohistochemical (IHC) markers was applied to achieve the diagnosis. These included calretinin, mesothelin, CK5/6, Hector Battifora mesothelial cell antibody (HBME), WT1, MOC31, CK7 and CK20. Histopathological correlation was done wherever possible.Result:In the present study, we compiled four cases of MM over 8 years diagnosed on serous effusion cytology and confirmed by immunocytochemistry (ICC)/cell block immunohistochemistry (IHC)/biopsy. This indicates a rare incidence of MM. The Cytological features of MM were studied.Conclusion:The diagnosis of MM is difficult, especially cytologically. It was found to be a rare entity in the malignant cases diagnosed on effusion cytology.

HEG1, BAP1, and MTAP are useful in cytologic diagnosis of malignant mesothelioma with effusion.

The specificity and sensitivity of HEG1 for malignant mesothelioma (MM) is high. The use of BAP1/MTAP immunohistochemistry (IHC) is recommended to separate benign and malignant mesothelial proliferations. We determined how ancillary techniques can be used for the cytological diagnosis of MM with effusion. Cell blocks from effusions from cases with MM, reactive mesothelial cells (RMCs), and carcinomas were analyzed by IHC with HEG1, BAP1, and MTAP and with homozygous deletion (HD) of CDKN2A by fluorescence in situ hybridization. Staining scores were calculated for IHC by adding the number of categories for the staining intensity and the staining extension. HEG1 was positive in all (41/41) MMs, but negative in carcinomas, except for ovarian carcinomas. Overall 76.9% (20/26) of RMCs and 28.6% (6/21) of ovarian carcinomas expressed HEG1. BAP1 loss was found in 71.1% of MMs, but none was found in RMCs. MTAP loss was found in 76.2% of MMs, but none was found in RMCs. 73.9% of MMs harbored HD of CDKN2A. There was concordance between loss of MTAP and HD of CDKN2A in 95% of MMs. HEG1 is a good marker for mesothelial differentiation in effusion cytology. HD of CDKN2A is frequently observed in cell blocks from effusions of MMs, and MTAP IHC may act as a surrogate for HD of CDKN2A. Cell block analysis is recommended for effusions of unknown origins with the following methods: IHC with HEG1 and claudin 4 to validate the mesothelial origin, followed by BAP1 and MTAP IHC to confirm malignancy.

Aquaporin-1 expression in fluoro-edenite-induced mesothelioma effusions: An approach by cell-block procedure.

Aquaporin 1 (AQP-1) is a water channel protein found in cell membranes, whose expression has been considered an independent favourable prognostic factor in pleural malignant mesothelioma (MM). The aim of this study was to evaluate the expression of AQP-1 and its prognostic value in a series of pleural MM effusions, from a geographical area with high concentrations of fluoro-edenite (FE). We selected 25 MM cases from Biancavilla (Italy), an area with high environmental concentrations of FE. Cytological samples, cell-blocks (CB), clinical and follow-up data were available for all cases. Immunohistochemistry for calretinin, CK5/6, WT1, CK7 and TTF1 was used on CB sections to confirm the cytological diagnosis of MM. Immunohistochemistry for AQP-1 was performed and high expression was defined when ≥50% of tumour cells showed linear and circumferential membranous staining. The cohort included 16 men and nine women (median age: 67.5years; range: 49-88years). The median survival was 14months (range 1.5-60months), with a significant value (P = 0.006). All cases have been histologically confirmed and classified as epithelioid (16 cases), biphasic (seven cases) and sarcomatoid (two cases). AQP-1 high expression has been observed in 16 cases. Comparing AQP-1 high expression to the survival of corresponding patients, a significant association with a slight increased overall survival of 12months has been demonstrated. Nine patients with a AQP-1 score less than 50% showed a shorter median overall survival (7months). AQP-1 high expression is detectable on cytological samples of FE-induced MM with a prognostic value.

Guidelines for cytopathologic diagnosis of epithelioid and mixed type malignant mesothelioma. Complementary statement from the International Mesothelioma Interest Group, also endorsed by the International Academy of Cytology and the Papanicolaou Society of Cytopathology.

To provide practical guidelines for the cytopathologic diagnosis of malignant mesothelioma (MM). Cytopathologists involved in the International Mesothelioma Interest Group (IMIG) and the International Academy of Cytology (IAC), who have an interest in the field contributed to this update. Reference material includes peer-reviewed publications and textbooks. This article is the result of discussions during and after the IMIG 2012 conference in Boston, followed by thorough discussions during the 2013 IAC meeting in Paris. Additional contributions have been obtained from cytopathologists and scientists, who could not attend these meetings, with final discussions and input during the IMIG 2014 conference in cape town. During the previous IMIG biennial meetings, thorough discussions have resulted in published guidelines for the pathologic diagnosis of MM. However, previous recommendations have stated that the diagnosis of MM should be based on histological material only.[12] Accumulating evidence now indicates that the cytological diagnosis of MM supported by ancillary techniques is as reliable as that based on histopathology, although the sensitivity with cytology may be somewhat lower.[345] Recognizing that noninvasive diagnostic modalities benefit both the patient and the health system, future recommendations should include cytology as an accepted method for the diagnosis of this malignancy.[67] The article describes the consensus of opinions of the authors on how cytology together with ancillary testing can be used to establish a reliable diagnosis of MM.

Pleural mesothelioma. Cytology and molecular diagnostics

The definitive diagnosis of malignant mesothelioma (MM) in effusion cytology is often avoided or reluctantly made by cytology alone. The most probable reason for this skepticism is the lack of expertise in cytology among many pathologists and clinicians. When an effusion specimen is composed of cells with unequivocal cytological features of malignancy that have the morphology and immunophenotype of mesothelial cells, the cytological diagnosis of MM is straightforward. However, in the daily routine difficult cases of atypical mesothelial cells are often encountered and additional methods are required to establish an accurate diagnosis. In contrast to reactive mesothelial cells cells of MMs often harbor chromosomal aberrations, most frequently a polysomy in combination with a 9p21 deletion. These chromosomal aberrations can easily be detected by multitarget fluorescence in situ hybridization (FISH); therefore, FISH allows a reliable distinction between reactive mesothelial cells and MM cells. In order to be able to discriminate between MM and adenocarcinoma, an immunocytochemical panel consisting of different mesothelial and epithelial markers is very helpful. In most inconclusive cases of atypical mesothelial cells the combination of morphology, immunocytochemistry and FISH allows a better distinction between reactive mesothelial cells and MM in effusion cytology.

The diagnosis of malignant mesothelioma in effusion cytology

The diagnosis of malignant mesothelioma (MM) in effusion specimens is controversial. At the study institution (Northwestern University), a primary diagnosis of MM is made on fluid cytology specimens. In an effort to estimate the practice at other institutions, a survey was disseminated regarding cytologic diagnosis of MM. The authors also evaluated their own institution's experience with primary cytologic diagnosis of MM. Patients with MM at the study institution were identified from 1992 through 2011. Fluid cytology specimens preceding histologic diagnoses were reviewed. A survey was sent to a number of cytology laboratories to assess practice patterns regarding the diagnosis of MM. At the study institution, 20 cases of MM had effusion specimens preceding the diagnostic histologic material. In 6 cases (30%), a definitive diagnosis of MM was rendered via cytology alone. There were no false-positive diagnoses of MM. Of 55 laboratories that responded to the survey, 36 reported making a definitive diagnosis of MM after cytologic analysis. Almost all laboratories (35) willing to diagnose MM in effusions reported performing immunohistochemistry to distinguish adenocarcinoma from MM. A smaller proportion (18) of these laboratories reported doing additional immunohistochemistry or fluorescence in situ hybridization for p16 to help distinguish benign from malignant mesothelial proliferations. Those who do not definitively diagnose MM in fluid specimens state inability to identify invasion and overlap with reactive mesothelial proliferation as factors supporting their practice. Most respondents (32) felt that the clinicians at their institution would manage a patient based on a cytologic diagnosis of MM. The majority of respondents reported making a definitive diagnosis of MM in effusion cytology specimens. The diagnosis of MM in effusions, although not sensitive, is extremely specific.

Small orangiophilic squamous‐like cells: An underrecognized and useful morphological feature for the diagnosis of malignant mesothelioma in pleural effusion cytology

The cytological diagnosis of malignant mesothelioma (MM) on serous effusion is challenging due to significant morphologic overlap with reactive mesothelial cells and adenocarcinoma. One of the morphologic features of MM in effusion cytology, small orangiophilic squamous-like cells (SOSLC), has received little attention. To the best of the authors' knowledge, the current study is the first to assess the sensitivity and specificity of SOSLC in serous effusion specimens from histology-proven MM cases along with those of reactive mesothelial and adenocarcinoma cases. A total of 130 cases of pleural (86 cases) and peritoneal (44 cases) effusion cytology cases (30 with histology-proven MM, 41 with adenocarcinoma, and 59 with reactive mesothelial cells) were studied. The presence or absence of SOSLC was recorded in each case. The cytological diagnoses of the 30 histology-proven MM cases included 1) atypical mesothelial cells, favor reactive (4 cases); 2) atypical mesothelial cells, suspicious for or cannot exclude mesothelioma (18 cases); and 3) positive for MM (8 cases). SOSLC were found in 10 of the 30 MM effusion cases (33.3%), 1 of the 41 adenocarcinoma cases (2.4%), and 5 of the 59 reactive mesothelial cell cases (8.5%). SOSLC were more likely to be present in MM effusions compared with either adenocarcinoma (P<.0001) or reactive mesothelial cell (P<.02) effusions. All 10 cases of MM with SOSLC were from pleural fluids. One case of peritoneal serous adenocarcinoma had SOSLC and 5 cases of reactive mesothelial cells in peritoneal fluid were found to have SOSLC. Although not sensitive, the presence of SOSLC is quite specific for MM in pleural fluid cytology specimens. Finding this morphological feature in pleural fluid should alert the pathologist to a possible diagnosis of MM.

Guidelines for Pathologic Diagnosis of Malignant Mesothelioma: 2012 Update of the Consensus Statement from the International Mesothelioma Interest Group

Malignant mesothelioma (MM) is an uncommon tumor that can be difficult to diagnose. To provide updated practical guidelines for the pathologic diagnosis of MM. Pathologists involved in the International Mesothelioma Interest Group and others with an interest in the field contributed to this update. Reference material includes peer-reviewed publications and textbooks. There was consensus opinion regarding (1) distinction of benign from malignant mesothelial proliferations (both epithelioid and spindle cell lesions), (2) cytologic diagnosis of MM, (3) key histologic features of pleural and peritoneal MM, (4) use of histochemical and immunohistochemical stains in the diagnosis and differential diagnosis of MM, (5) differentiation of epithelioid MM from various carcinomas (lung, breast, ovarian, and colonic adenocarcinomas, and squamous cell and renal cell carcinomas), (6) diagnosis of sarcomatoid mesothelioma, (7) use of molecular markers in the diagnosis of MM, (8) electron microscopy in the diagnosis of MM, and (9) some caveats and pitfalls in the diagnosis of MM. Immunohistochemical panels are integral to the diagnosis of MM, but the exact makeup of panels used is dependent on the differential diagnosis and on the antibodies available in a given laboratory. Immunohistochemical panels should contain both positive and negative markers. It is recommended that immunohistochemical markers have either sensitivity or specificity greater than 80% for the lesions in question. Interpretation of positivity generally should take into account the localization of the stain (eg, nuclear versus cytoplasmic) and the percentage of cells staining (>10% is suggested for cytoplasmic membranous markers). These guidelines are meant to be a practical reference for the pathologist.

Using fluorescent in situ hybridisation to diagnose mesothelioma in effusion cytology: the auckland experience so far with emphasis on difficult cases

<h3>Aims</h3> To evaluate the clinical, radiological and cytological features of cases where fluorescent <i>in situ</i> hybridisation (FISH) was used in effusion cytology for suspected malignant mesothelioma. Cytology, immunohistochemistry and FISH will be correlated with histology. We will also briefly discuss problem cases. <h3>Methods</h3> The cytology database was searched for all effusion cytology cases where FISH was requested to distinguish reactive mesothelium from malignant mesothelioma. Clinical history, radiology, cytology, immunohistochemistry, FISH findings and histology were reviewed. <h3>Results</h3> The mesothelioma FISH panel was requested in nine cases since it became available at LabPlus in March 2010. Median age was 71 and most patients presented with recurrent pleural effusions and pleural thickening or masses on CT scan. One patient had an unusual clinical presentation and two patients had atypical radiological findings. Histological confirmation of malignant mesothelioma was available in seven cases. FISH indicated malignancy in six of these. The remaining case that was negative for malignancy on FISH showed suspicious cytology and immunohis-tochemistry compatible with malignant mesothelioma. <h3>Conclusions</h3> FISH is useful in the cytological diagnosis of malignant mesothelioma. However, results should be interpreted with caution and in conjunction with clinical, radiological and cytologi-cal findings.

Parakeratotic-like cells in effusions — A clue to diagnosis of malignant mesothelioma

Background:Malignant mesothelioma (MM) is an aggressive neoplasm with a poor prognosis. Its incidence has been increasing worldwide. Cytological examination of an effusion is often the first opportunity to diagnose MM. However, the cytological diagnosis of MM can be difficult. We have noticed that parakeratotic-like cells, with orange cytoplasm and pyknotic nuclei, are present in many cases of mesothelioma on Papanicolaou-stained cytology slides. Although this cytological finding has been described previously, to our knowledge, there has been no systematic study of this finding. Our study is to determine whether the presence of small parakeratotic / orangeophilic cells (PK-like cells) is specific for the cytodiagnosis of mesothelioma.Materials and Methods:A total of 90 body fluid cases were selected from our archived specimens in the Cytology Section at the University of Chicago Hospital accessioned between January 2000 to November 2011. They included 30 cases of mesothelioma, 30 cases of adenocarcinoma, and 30 cases of reactive mesothelial cells.Results:PK-like cells were present in 83% of the mesothelioma cases, 13% of the adenocarcinoma cases, and 7% of the reactive cases. Our data showed that the presence of PK-like cells has a specificity of 90%, sensitivity of 83%, positive predictive value of 81%, and negative predictive value of 84% for the diagnosis of malignant mesothelioma in body cavity fluids.Conclusion:The presence of PK-like cells in the effusion specimen, especially in pleural effusions, is a highly specific and moderately sensitive cytological feature for diagnosis of mesothelioma.

Usefulness of EMA, GLUT-1, and XIAP for the Cytologic Diagnosis of Malignant Mesothelioma in Body Cavity Fluids

We compared the effectiveness of epithelial membrane antigen (EMA) with 2 newly described markers, X-linked inhibitor of apoptosis protein (XIAP) and an isoform of glucose transporter (GLUT-1), in the distinction between malignant mesothelioma (MM) and benign effusion (BE) in body cavity fluids. Immunohistochemical studies were performed on cell block sections from 35 cases of histologically confirmed MM and 38 BEs, using antibodies to EMA, XIAP, GLUT-1 (GLUT-1m, monoclonal; GLUT-1p, polyclonal). Results were graded based on the percentage of cells staining: negative (0%), 1+ (<25%), 2+ (25%-49%), 3+ (50%-74%), and 4+ (75%-100%). The performance of each marker was compared using receiver operating characteristic curve analysis. EMA demonstrated the best accuracy, with an area under the curve of 0.91 as compared with XIAP (0.67), GLUT-1m (0.74), and GLUT-1p (0.80). Based on these findings, EMA is a better marker than XIAP or GLUT-1 for the diagnosis of MM.

9p21 Deletion in the diagnosis of malignant mesothelioma in serous effusions additional to immunocytochemistry, DNA-ICM, and AgNOR analysis

The diagnosis of malignant mesothelioma (MM) in serous effusions is difficult but may be achieved by the application of adjuvant methods. The authors cytologically diagnosed 33 effusions as suspicious or positive for MM cells by using DNA-image cytometry (DNA-ICM), immunocytochemistry and AgNOR analysis. The authors further detected 9p21 deletions by chromosomal fluorescence in situ hybridization (FISH). In addition, 31 cases of metastatic carcinomas and 39 of tumor cell-negative effusions were investigated. All diagnoses were confirmed by histologic and/or clinical follow-up. DNA aneuploidy was found in 71% of MMs, 100% of metastatic carcinomas, and in none of the negative effusions. Calretinin was positive in 100% of MMs, in none of the metastatic carcinomas, and in 94.9% of negative effusions. BerEP4 showed positivity in 15.6% of MMs, 87.1% of metastatic carcinomas, and in none of the negative effusions. With AgNOR analysis, 89.3% of MMs and 96.7% of metastatic carcinomas showed >or=2.5 AgNOR dots as satellites and >or=4.5 as total AgNOR counts. 9p21 deletions were demonstrated in 90.9% of MM cases, 45.2% of metastatic carcinomas, and in none of the negative effusions. By cytology alone, 81.8% of MMs were identified unequivocally. Addition of DNA-ICM improved the prevalence of tumor cell detection to 87.9% and of AgNOR analysis to 97%. The introduction of 9p21 deletions by FISH improved this prevalence to 100%. Because of these results, the authors propose the sequential application of immunocytochemistry, DNA-ICM, and AgNOR analysis to establish a cytological diagnosis of malignant mesothelioma in serous effusions. In persistent doubtful diagnoses, the authors recommend fluorescence in situ hybridization to analyze the 9p21 deletion.

Early cytological diagnosis of diffuse malignant mesothelioma of the peritoneum: A case report

Mesotheliomas are the most frequent primary malignant tumors of serosal cavities with a poor prognosis. A definitive and early diagnosis on effusion samples is important, because recent advances in therapy for patients with mesothelioma may result in an improved outcome if they are applied to stage I disease. We report a case of malignant peritoneal mesothelioma diagnosed repeatedly by cytology in ascites fluids 1.5 yr before the diagnosis was confirmed by biopsy histology. The cytological diagnoses were supported by immunocytochemistry, DNA-cytometry, and AgNOR-analysis. Routine cytology supported by three adjuvant methods enabled us to correctly establish the diagnosis. Our case suggests that a cytological diagnosis of malignant mesothelioma supported by adjuvant methods should not be rejected even if based on negative histological results.

Cytological diagnosis of malignant mesothelioma—improvement by additional analysis of hyaluronic acid in pleural effusions

Cytology allows the diagnosis of malignant mesothelioma (MM) from effusions with high specificity but low sensitivity. Conversely, elevated levels of hyaluronic acid (HA) in effusions are sensitive indicators of MM, although specificity is insufficient. We studied whether the cytological diagnosis of MM could be improved by HA analysis. HA was analysed in patients with histologically confirmed MM (n=162), adenocarcinoma or other malignant tumours (n=100) and in 90 patients with benign pleural diseases. In 77 out of 162 effusions, all, and in 33 some, cytological criteria of MM were satisfied. The cut-off value of HA showing maximum diagnostic reliability (86%) regarding MM was 30 mg/l (sensitivity 87%, specificity 86%). A HA value of 100 mg/l yielded 39 and 98%, respectively. Seventy three out of 77 patients with cytological findings indicative of MM showed HA levels greater than 30 mg/l as well as 27 of 33 patients with suspicious lesions. These 100 patients were correctly recognised as having MM. The addition of HA analysis to cytology, requiring all or some criteria of MM as positive, increased sensitivity for MM from 48 to 71-91%, whereas specificity only slightly decreased to 94-96%. We conclude that the combined cytological and HA analysis of pleural effusions had the potential to improve the diagnosis of MM.

Single-arm, open label study of pemetrexed plus cisplatin in chemotherapy naïve patients with malignant pleural mesothelioma: Outcomes of an expanded access program

An expanded access program (EAP) provided patient access to pemetrexed prior to its commercial availability. The current report consists of US patients in the EAP who had chemotherapy naïve pleural mesothelioma. Eligible patients had a histologic or cytologic diagnosis of malignant mesothelioma that was not amenable to curative treatment with surgery. Study treatment consisted of pemetrexed 500mg/m(2) in combination with cisplatin 75mg/m(2) once every 21 days. Vitamin B12, folic acid, and dexamethasone were administered as prophylaxis. Serious adverse events (SAEs) were reported by investigators and compiled in a pharmacovigilance database for all patients enrolled in the EAP. Of 1056 patients receiving at least one dose of pemetrexed in the EAP, 728 had chemotherapy naïve pleural mesothelioma. Median age of this group was 70 years (range 23-89 years) and 84% were male. Among 615 patients, overall response rate was 20.5%, including 12 complete responses (2.0%) and 114 partial responses (18.5%). An additional 290 patients (47.2%) had stable disease. Median survival for all 728 patients was 10.8 months (95% CI=9.8, 12.3; 60.3% censorship) and 1 year survival was 45.4%. The most commonly reported SAEs in the overall EAP irrespective of causality were dehydration (7.2%), nausea (5.2%), vomiting (4.9%), dyspnea (3.8%), and pulmonary embolism (2.4%). In this large cohort, 67.7% of patients treated with first-line chemotherapy experienced a response or stable disease. Survival time and toxicity from this EAP were promising for this difficult-to-treat disease.

Absence of SV-40 large T antigen (Tag) in malignant mesothelioma effusions: an immunocytochemical study.

Simian Virus 40 (SV 40) was recently implicated in the pathogenesis of malignant mesothelioma. The oncogenic capacity of SV-40 is a function of a nuclear protein, the large T antigen (Tag). SV-40 Tag DNA sequences are detected by the polymerase chain reaction in 40-80% of malignant mesothelial proliferations. However, the role of immunohistochemistry (IHC) in demonstrating the nuclear localization of Tag is controversial. We sought to determine the clinical utility of SV-40 Tag IHC in pleural effusion cytology as an ancillary tool in the cytologic diagnosis of malignant mesothelioma (MM). Formalin-fixed, paraffin-embedded cell block sections from 100 pleural effusions (32 MMs, 25 benign reactive, 43 metastatic adenocarcinomas) were immunostained for the SV-40 anti-Tag, using two primary monoclonal SV-40 Tag antibodies: clone Pab 416 and clone Pab 101. Despite strong and consistent immunoreactivity in positive controls, no nuclear immunostaining was observed in any case. We believe the small sample size in cytology cell block sections, the low viral copy number in infected cells, and the effect of formalin fixation may have resulted in absence of immunoreactivity. The role of SV-40 Tag IHC in diagnostic cytopathology remains unclear unless further studies reliably show its detection.

Cytologic diagnosis of malignant mesothelioma in serous effusions using an antimesothelial-cell antibody.

Differentiating mesothelioma, reactive mesothelium, and adenocarcinoma in serous effusions is often difficult, despite the application of ancillary techniques in support of the traditional cytomorphologic criteria. A polyclonal antimesothelial-cell antibody recently developed by our group was evaluated as a histogenetic marker on a series of primary (n = 12) and metastatic (n = 12) malignant effusions. Immunostaining was performed on paraffin sections from cell blocks. All mesothelioma effusions stained positive for the antibody, whereas, in contrast, all metastatic carcinoma specimens failed to react. These results (100 percent specificity and 100% sensitivity for mesothelioma) provide a basis for a reliable use of the antibody in the cytologic examination of suspicious or malignant serous effusions.