The use of immunohistochemistry in distinguishing reactive from neoplastic mesothelium. A novel use for desmin and comparative evaluation with epithelial membrane antigen, p53, platelet‐derived growth factor‐receptor, P‐glycoprotein and Bcl‐2

Abstract

Desmin and EMA appear to be the most useful markers in distinguishing benign from malignant mesothelial proliferations. Desmin appears to be preferentially expressed in reactive mesothelium and EMA appears to be preferentially expressed in neoplastic mesothelium. The complementary use of both markers is advocated in ascertaining the nature of mesothelial proliferations. Immunohistochemical detection of mutated p53 oncoprotein appeared to be of less utility in this study on account of the low marker sensitivity for malignant mesothelioma. However, p53 antibody may be of use as a second-line marker of neoplastic mesothelium within a standard immunohistochemical panel of antibodies. In this study, Bcl-2, P-glycoprotein and PDGF-R beta-chain appear to be of no use in distinguishing reactive from neoplastic mesothelium, although more formal evaluation of these markers is required.

An improved flow cytometric assay for detection and discrimination between malignant cells and atypical mesothelial cells, in serous cavity effusions

“…Desmin has been detected in benign mesothelial cells, while minimal expression is documented in cases of carcinoma and malignant mesothelioma (10,20,31). In this study, a FCM option of desmin-33 assessment on suspicious cells was provided, which proved to have high sensitivity and specificity for malignancy detection.…”

“…However, desmin has been studied by immunohistochemistry and found to be positive in only 10% of malignant mesothelioma cases, compared with reactive mesothelial hyperplasias (85%); (32). Thus, differential diagnostic evidence between adenocarcinoma and malignant mesothelioma could theoretically be provided by investigating Ber-EP4 and desmin-33 expression (expected positive and negative, respectively, in adenocarcinoma, while both negative in malignant mesothelial cells) (31,32). It is also important to underline that among the eight cases rated atypical by CC in this series, three cases were considered mesothelial cells by desmin-33 positivity, and thus FCM contributed to the final diagnosis.…”

Mesotheliomas with small cell features: report of eight cases

“…47 Another marker that can be useful in this differential diagnosis is bcl-2, which has been reported to be expressed in 79 to 100% of synovial sarcomas, but in only 0 to 10% of mesotheliomas. [48][49][50][51] It should be mentioned, however, that TLE1, a marker that has an important role in the Wnt pathway and that has been shown to be a highly sensitive and specific immunohistochemical marker for synovial sarcoma, 52 was found in a recent study to be variably expressed in about 70% of mesotheliomas regardless of their histomorphologic subtype, thus demonstrating that immunostaining for this marker has little or no value in discriminating between synovial sarcomas and mesotheliomas. 53 Additionally, the demonstration of the distinctive t(x;18)(p11;q11) translocation that is reportedly present in nearly all synovial sarcomas can help to establish the correct diagnosis.…”

Selected other problematic testicular and paratesticular lesions: rete testis neoplasms and pseudotumors, mesothelial lesions and secondary tumors

“…Desmin has recently been shown to have value in this differential as it is infrequently expressed in malignant mesothelioma and commonly positive in hyperplasia. 25 Metastatic adenocarcinoma is a rare differential diagnostic consideration. Low-power observation of a linear disposition of the tubules rather than a haphazard infiltrative growth, reactive background such as of an organizing hematocele (Figure 8a) and positivity for mesothelial markers confirm reactive mesothelial hyperplasia (Figure 8c) rather than metastatic adenocarcinoma.…”