Malignant pleural mesothelioma in a female lion (Panthera leo)

Our plain-English summary of Malignant pleural mesothelioma in a female lion (Panthera leo), by E. Bollo, F.E. Scaglione, M. Tursi, et al (Research in Veterinary Science, 2011).

The study

• Authors: E. Bollo, F.E. Scaglione, M. Tursi, C. Schröder, G. Degiorgi, E. Belluso, S. Capella, D. Bellis
• Journal: Research in Veterinary Science
• Published: 2011;91(1):116-118
• Type of article: Case report
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

An 18-year-old female lion (Panthera leo) was referred to the Department of Animal Pathology of the University of Turin (Italy). At necropsy, multiple nodular, 4-20-mm, confluent white firm nodules were scattered throughout the pleural surfaces of the thoracic wall and of the lungs. Histological lesions were represented by proliferations of papillary structures lined by cuboidal basophilic mesothelial cells with large, oval nuclei and abundant granular eosinophilic cytoplasm. Immunohistochemistry revealed immunoreactivity for pancytokeratin and vimentin. None of the cells expressed calretinin antigen. Asbestos fibers and asbestos bodies were not detected respectively by light microscopy and by Scanning Electron Microscope-Energy Dispersive Spectrometer investigations. On the contrary, chrysotile asbestos were identified in samples from shelter material. Histological and immunohistochemical findings were consistent with the diagnosis of an epithelial malignant mesothelioma. To our best knowledge, this is the first report of a pleural mesothelioma in a lion.

Copyright © 2010 Elsevier Ltd. All rights reserved.

In plain English

This was a case report about one animal. An 18-year-old female lion, kept all its life in a northern Italian zoo, died suddenly and was examined after death at the University of Turin. At night it was kept in a shelter covered by asbestos-cement boards (Eternit). Many firm white nodules, 4 to 20 mm across, were scattered over the pleural surfaces of the chest wall and lungs. Tissue stains showed strong reactivity for pancytokeratin, weaker for vimentin and none for calretinin. From these, the authors diagnosed a papillary epithelioid malignant mesothelioma of the pleura. No asbestos fibers or asbestos bodies were found in the tumour or lung tissue, but chrysotile asbestos was identified in samples of the shelter material. The authors noted that absent calretinin staining conflicted with the diagnosis, but that calretinin had also proved negative in feline mesotheliomas and had not yet been investigated in lions. They suggested that short fibers may have been cleared from the body. The authors wrote that a link between inhaled asbestos fibers and the tumour "may be easily hypothesized."

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Case report: post-mortem (necropsy) examination of a single animal, described by the authors as the first report of a pleural mesothelioma in a lion
• Who was studied: One 18-year-old female lion (Panthera leo), referred for necropsy to the Department of Animal Pathology, University of Turin, Italy, after sudden death
• Exposure: Lifelong nightly housing in a zoo shelter in northern Italy covered by asbestos-cement boards (Eternit); chrysotile was later identified in shelter material
• Main results:
  • At necropsy, many confluent white firm nodules, 4 to 20 mm, were found on the pleural surfaces of the thoracic wall and lungs
  • The pleural nodules stained weakly and multifocally for vimentin and more intensely for pancytokeratin
  • No tumour cells stained for calretinin
  • The authors diagnosed a papillary epithelioid malignant mesothelioma, confirmed in their view by co-expression of vimentin and pancytokeratin
  • No asbestos fibers or asbestos bodies were detected in tumour and lung tissue by light microscopy and SEM-EDS
  • Chrysotile asbestos was identified by X-ray diffraction in samples of the shelter material
  • The liver mass was a biliary cystadenoma
• The authors' conclusion: The authors stated that a link between inhalation of asbestos fibers from the shelter and the tumour may be hypothesized, as described in humans
• Limitations the authors state:
  • The negative calretinin staining conflicts with a mesothelioma diagnosis, although the authors note calretinin has been negative in feline mesotheliomas and has not been studied in lions
  • No asbestos fibers were found in the tissues; the authors suggest short fibers and asbestos dust may have been readily cleared

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Pathology, Autopsy, Mesothelial Cells, Eosinophilic, Immunohistochemistry, Calretinin, Asbestos Bodies.

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