Malignant mesothelioma: a comparison of biopsy and postmortem material by light microscopy and immunohistochemistry

Abstract

Aims—The diagnosis of malignant mesothelioma in pleural biopsies can be difficult. Survival is short and consequently many of these cases are submitted to necropsy to assist with medicolegal claims. This study compares the histological appearances and immunohistochemical profile of nine biopsy specimens with corresponding postmortem specimens.

Methods—Archival, formalin fixed, paraffin wax embedded material was obtained from nine biopsy and corresponding postmortem cases of malignant mesothelioma. The specimens were examined by light microscopy and stained with an immunohistochemical panel of 12 commercially available antibodies including CAM5.2, HBME-1, and Ber-EP4, and antibodies to thrombomodulin, calretinin, CD44H, WT-1, carcinoembryonic antigen, Leu-M1, epithelial membrane antigen and p53.

Results—There was greater variation in the range of histological appearances of mesotheliomas in postmortem specimens compared with biopsy specimens. There was also variability in the immunohistochemical staining pattern for certain antibodies including HBME-1, and Ber-EP4 and antibodies to calretinin, CD44H, WT-1, and p53.

Conclusions—All available information should be taken into account in the histological diagnosis of malignant mesothelioma. Interpretation of the immunohistochemical profile should be regarded with some caution when only postmortem material is available. When reporting a postmortem case of suspected mesothelioma, the pathologist should seek to review all available biopsy material in conjunction with the necropsy.