Cytologic differential diagnosis among reactive mesothelial cells, malignant mesothelioma, and adenocarcinoma

Abstract

BACKGROUND The differential diagnosis between reactive mesothelial cells (RMs), malignant mesotheliomas (MMs), and adenocarcinomas (ACs) is often difficult in cytologic specimens, and the utility of various immunohistochemical markers have been explored. Because recent immunohistologic studies have suggested that E‐cadherin (E‐cad) and calretinin (Cal) may be useful markers for epithelial and mesothelial differentiations, respectively, the authors investigated their utility in cytologic diagnosis. METHODS In this retrospective study, immunostaining was performed on smears retrieved from Papanicolaou‐stained slides of effusions using the labeled streptavidin‐biotin method. Sixteen cases of RM, 9 cases of MM, and 52 cases of AC from various sites, including 13 pulmonary primaries, were examined with primary antibodies against E‐cad and Cal. RESULTS The positive rates for E‐cad and Cal, respectively, were as follows: RM, 0/16 (0%) and 16/16 (100%); MM, 9/9 (100%) and 8/8 (100%); and AC, 45/52 (86.5%) and 0/51 (0%). The E‐cad expression by neoplastic cells was strongest in the intercellular junctions, and poorly differentiated neoplastic cells in the single cell form showed the weakest expression. CONCLUSIONS In contrast to the results of previous immunohistochemical studies, the current study indicates that MMs constantly express E‐cad, whereas RMs lack its expression in cytologic specimens, which would be useful in the differential diagnosis between the two. On the other hand, E‐cad expression is not reliable for distinguishing AC from MM. The Cal expression can be a very useful marker for the distinction between AC and the mesothelial lineage. The combined immunostaining for E‐cad and Cal has utility in differential diagnosis among RM, MM, and AC. Cancer (Cancer Cytopathol) 2000;90:55–60. © 2000 American Cancer Society.

Evaluation of a Panel of Molecular Markers for the Diagnosis of Malignant Serous Effusions

“…In some immunocytochemical studies, CALB2 was positive in most of benign effusions (94-100%; refs. 12,20). It is difficult to compare these results with ours, because the expression of CALB2 was detected at two different levels (protein or mRNA).…”

“…Therefore, if Ep-CAM seems to be of limited interest to distinguish carcinoma from mesothelioma effusions, it is a valuable molecular marker for the detection of tumor cells in serous effusions. CDH1, an epithelial-specific adhesion molecule, has been proven to reliably distinguish carcinoma cells from benign reactive mesothelial cells, but not from mesothelioma cells, in serous effusions by immunocytology (12,20,33). We also found that CDH1 was specifically expressed in malignant epithelial and nonepithelial serous effusions, but it was not very sensitive.…”

Evaluation of 12 antibodies for distinguishing epithelioid mesothelioma from adenocarcinoma: identification of a three-antibody immunohistochemical panel with maximal sensitivity and specificity

“…A few potentially useful markers, such as E-cadherin and N-cadherin, were omitted because of conflicting reports about their performance in distinguishing mesothelioma from AdCA. 57,[69][70][71][72] A third strength of our study was the detailed statistical analysis, which distinguishes this study from most previous studies in this area. Not only were all antibodies evaluated by univariate analysis to determine their abilities to distinguish MEM from all AdCA ( Table 2, column 2), but the relative utility of each antibody was quantified by ROC curve analysis ( Table 2, column 3), the relevant sensitivities and specificities were calculated for each MEM-and AdCA-associated antibody (Table 3), and LR was applied to determine the optimal combination of antibodies for distinguishing MEM from AdCA.…”

False‐positive interpretations in respiratory cytopathology: Exemplary cases and literature review

“…33 Another assessment by Kitazume et al demonstrated that reactive mesothelial cells typically lack E-cadherin whereas virtually all malignant mesotheliomas express that marker along with 85% of adenocarcinomas. 34 Davidson et al also showed that desmin was present in 84% of reactive mesothelial cells, as compared with 2% of carcinomas and 8% of mesotheliomas. 35 Simulants of Small Cell Carcinoma (Table III) We would be remiss if we failed to mention the false-positive diagnosis of small cell carcinoma in patients with reserve cell bronchial hyperplasia, follicular bronchitis, or non-Hodgkin lymphoma.…”