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J Clin Pathol 66:847-853 doi:10.1136/jclinpath-2012-201303
  • Review

Challenges and controversies in the diagnosis of mesothelioma: Part 1. Cytology-only diagnosis, biopsies, immunohistochemistry, discrimination between mesothelioma and reactive mesothelial hyperplasia, and biomarkers

  1. Sonja Klebe1,2
  1. 1Department of Surgical Pathology, SA Pathology, Flinders Medical Centre, Bedford Park, South Australia
  2. 2Flinders University, Adelaide, South Australia
  3. 3Asbestos Diseases Research Institute (ADRI), Sydney, New South Wales, Australia
  1. Correspondence to Professor Douglas W Henderson, Department of Surgical Pathology, SA Pathology at Flinders Medical Centre, Bedford Park 5042, South Australia; dhenderson{at}internode.on.net; Doug.Henderson{at}health.sa.gov.au
  • Received 8 March 2013
  • Revised 7 June 2013
  • Accepted 8 June 2013
  • Published Online First 27 June 2013

Abstract

The detection of neoplastic invasion remains the linchpin for a clear diagnosis of malignant mesothelioma. Cytology-only diagnosis of epithelioid mesothelioma on aspirated effusion fluid remains controversial. A major problem is poor sensitivity, although cytodiagnosis is achievable in many cases at a high order of specificity, especially when a large volume of effusion fluid is submitted for cytological evaluation, enabling the preparation of cell-block sections for immunohistochemical investigation and when the cytological findings can be correlated with imaging studies to assess the anatomical distribution of the lesion and evidence of nodularity of the pleural disorder and, in some cases, to demonstrate evidence of invasion. Although ‘positive’ and ‘negative’ immunohistochemical markers have proved remarkably effective in distinguishing between epithelioid mesothelioma and secondary carcinoma and other malignant tumours metastatic to serosal membranes, no mesothelial marker has 100% sensitivity and specificity for mesothelioma diagnosis, so that panels of ‘positive’ antibodies and markers with negative predictive value are required. At present, no tissue or serum marker (including the molecular detection of p16/CDKN2A) has been proved to have sufficient specificity, consistency and reproducibility that it can replace evidence of invasion as the decisive marker for diagnosis when there is any uncertainty concerning a diagnosis of epithelioid mesothelioma and in the case of atypical fibrous lesions of the pleura (especially collagen-rich lesions, namely fibrous pleuritis vs desmoplastic mesothelioma), in which even the assessment of invasion can be problematical as illustrated in part 2 of this review.

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