Cancer Cytopathology. 2008 Feb 27 [Epub ahead of print] [Link]

Onofre FB, Onofre AS, Pomjanski N, Buckstegge B, Grote HJ, Böcking A.

Institute of Cytopathology. Heinrich‐Heine University, Dusseldorf, Germany.


Background: The diagnosis of malignant mesothelioma (MM) in serous effusions is difficult but may be achieved by the application of adjuvant methods.

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.

Results: 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 2.5 AgNOR dots as satellites and 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%.

Conclusions: 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.

Keywords: 9p21, CDKN2A, fluorescence in situ hybridization, DNA-ICM, AgNOR analysis, immunocytochemistry, mesothelioma, effusion