[Cell-block immunocytochemical characterization of effusions. Use of antibody panel: calretinin, Ber-EP4, keratin and CD68].

An anticorpal panel formed by Calretinin, Ber-EP4, Keratin and CD 68 has been applied to differentiate mesothelial hyperplasia/mesothelioma from metastastic carcinoma in cavity effusions. The study was performed in 86 cases in which paraffinated cell-blocks were obtained. All cases positive for malignancy had histological confirmation. The series included 2 malignant mesothelioma, 54 reactive mesothelial hyperplasia, and 30 metastatic carcinoma. All cases of reactive mesothelial showed strong cytoplasmatic positivity for Calretinin, and hyperplasia negativity for Ber-EP4. The 2 cases of mesothelioma were positive for Calretinin and negative for Ber-EP4. In contrast, all cases of metastatic carcinoma had membrane or cytoplasmatic positivity for Ber-EP4. The sensitivity (100%) and specificity (100%) of reactivity for Calretinin and Ber-EP4 showed that the immunocytochemical results on paraffin embedded material from cavity effusions are very reliable, so that the tested immunocytochemical panel can be useful in cytological differential diagnosis between reactive mesothelial hyperplasia/mesothelioma and metastatic carcinoma.