To determine the value of calretinin and cytokeratin (CK) 5/6 in discriminating mesothelioma from adenocarcinoma in serous effusion specimens.
A total of 101 recent, histologically or clinically confirmed malignant effusions with immunostained cell block preparations were reviewed. The cases consisted of 34 mesotheliomas and 67 adenocarcinomas. This included 17 ascitic fluid and 84 pleural fluid samples. The adenocarcinomas included metastatic carcinomas from the breast (12), lung (19), stomach (3), colon (1), pancreas (2), ovary (6) endometrium (1) and 23 histologically confirmed metastases from unknown primary sites. The cases were assessed as negative or positive (>5% of cells stained). The staining pattern was recorded as cytoplasmic, cell membrane, nuclear or cytoplasmic and nuclear staining.
Calretinin staining was present in 97% (33/34) of the mesothelioma cases with a majority of them showing both cytoplasmic and nuclear staining (29/33). Only 3% (2/67) of adenocarcinomas were positive for calretinin, one being a lung adenocarcinoma and the other an adenocarcinoma of unknown primary site in an ascitic fluid. Cytokeratin 5/6 staining was also present in 33/34 (97%) of mesothelioma cases. Six (9%) adenocarcinomas were positive, including metastases from the lung (1), breast (1), ovary (2) and unknown primary site (2). Four of the six adenocarcinoma cases positive for CK5/6 were in ascitic fluids. No cases of mesothelioma were negative for both calretinin and CK5/6. Only one adenocarcinoma case, (which was from unknown primary site in an ascitic fluid sample), was positive for both markers.
The results confirm that calretinin and CK 5/6 are useful markers for mesothelioma in effusion specimens. CK5/6 staining may be less useful for peritoneal fluid specimens where metastatic adenocarcinomas may be more likely to express the antigen. Further study of ascitic/peritoneal specimens is warranted. However, positive staining, particularly for both antigens, is highly indicative of a mesothelial origin for cells. The two markers make a useful addition to EMA and the panel of adenocarcinoma markers routinely applied to effusion specimens.
"Cytokeratins (CK) are intermediate filaments located in the cytoplasm of virtually all epithelial cells and subsets of nonepithelial cells including mesothelial cells . More than 70 CK subtypes have been identified. "
[Show abstract][Hide abstract] ABSTRACT: Distinguishing malignant mesothelioma, adenocarcinoma and reactive mesothelial proliferation in both cytologic and surgical pathologic specimens is often a diagnostic challenge. Conventional cytomorphologic assessment is an important step in the differential diagnosis of these entities.
The pleural effusion cytologies from 40 cases of malignant mesothelioma, 40 cases of adenocarcinoma and 30 cases of reactive mesothelial proliferation diagnosed between 1997 and 2007 were reviewed. Twenty-seven cytologic features which are regarded as useful in the differential diagnosis of mesothelioma, adenocarcinoma and benign mesothelial proliferation were assessed. These cytologic features were subjected to a stepwise logistic regression analysis. Three features were selected to distinguish malignant mesothelioma from adenocarcinoma: giant atypical mesothelial cell (P = 0.0001), nuclear pleomorphism (P = 0.0001) and acinar structures (P = 0.0001), the latter two being characteristics of adenocarcinoma. The variables selected to differentiate malignant mesothelioma from reactive mesothelial cells were: cell ball formation (P = 0.0001), cell in cell engulfment (P = 0.0001) and monolayer cell groups (P = 0.0001), the latter being a feature of benign mesothelial proliferation. When these selected variables were subjected to a stepwise logistic regression analysis, the logistic model correctly predicted 90% of cases of benign mesothelial proliferation versus 97.5% of malignant mesothelioma and 92.5% of malignant mesothelioma versus 92.5% of adenocarcinoma.
Conventional cytomorphologic assessment is the first step to establish an accurate diagnosis in pleural effusions. Several cytologic features have predictive value to seperate malignant mesothelioma from adenocarcinoma and reactive mesothelial proliferation. Diagn. Cytopathol. 2009.
[Show abstract][Hide abstract] ABSTRACT: Multicystic peritoneal mesothelioma (MPM) is an uncommon cystic mesothelial proliferative lesion. It occurs predominantly in women of reproductive age and most commonly arises in the pelvis. The preoperative diagnosis of MPM is difficult to establish based on clinical and radiographic findings, and has therefore traditionally been diagnosed following surgical resection. Due to differing management of MPM and its differential diagnoses including both benign and malignant lesions, it would be beneficial to diagnose MPM preoperatively. We report a case of MPM in a middle aged female that was diagnosed by fine needle core biopsy and touch preparations, allowing for appropriate clinical management. The cytomorphologic features of needle core biopsy, immunocytochemical studies and differential diagnosis are discussed. Furthermore, despite its infrequency, the current case emphasizes the importance of the inclusion of this entity in the differential diagnosis of cystic lesions of the abdomen and pelvis at the time of on-site evaluation and final diagnosis, in order to avoid misinterpretation of strips of benign mesothelial cells as inadequate for diagnosis.
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