Predominantly fibrous malignant mesothelioma in a cat

Our plain-English summary of Predominantly fibrous malignant mesothelioma in a cat, by A.T. Weiss, A.B. da Costa, R. Klopfleisch (Veterinary Medicine International, 2010).

The study

• Authors: A.T. Weiss, A.B. da Costa, R. Klopfleisch
• Journal: Veterinary Medicine International
• Published: 2010;2010:396794
• Type of article: Case report
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Malignant mesotheliomas are rare tumours in domestic cats. They occur within the abdominal or thoracic cavity and are regularly associated with pleural or peritoneal effusions. The histopathological diagnosis can be quite challenging, as these neoplasms may resemble other epithelial or mesenchymal neoplasms. However, differentiation can be achieved by immunohistochemistry in most cases. Here we describe the rare case of a malignant mesothelioma of the fibrous subtype in the thoracic cavity of a cat and discuss differential diagnoses and treatment options for this tumor type.

In plain English

This was a case report about one cat. It shows what happened in a single animal, not how common the disease is. An approximately 15-year-old female domestic short hair cat died after several days of breathing difficulty and was examined after death at a veterinary pathology department in Berlin. The examination found 50 mL of clear, blood-tinged fluid in the chest and firm whitish nodules up to 6 × 5 × 3 mm on the chest lining. Under the microscope the tumour cells were mostly spindle-shaped, and the first diagnosis was fibrosarcoma. Staining showed that the cells carried both cytokeratin and vimentin. This led to a final diagnosis of predominantly fibrous malignant mesothelioma in the chest cavity, which had spread to a sternal lymph node and the lung. A separate lung nodule was a pulmonary adenocarcinoma. The article reported no asbestos or other exposure history for this cat, and the authors wrote that the cause of these tumours in domestic animals is unknown. The authors concluded that mesothelioma should be considered in cats with breathing difficulty, chest fluid and pleural thickening, and that immunohistochemistry should be used in diagnosis.

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 (single animal, post-mortem examination)
• Who was studied: One approximately 15-year-old female domestic short hair cat, submitted for necropsy to the Department of Veterinary Pathology, Freie Universitaet Berlin, Germany; date of the case not stated
• Exposure: No asbestos or other exposure history is reported for this cat. The authors state that the cause of spontaneous mesotheliomas in domestic animals is unknown.
• Main results:
  • The cat had died spontaneously after several days of dyspnoea (breathing difficulty).
  • At necropsy the thoracic cavity contained 50 mL of clear serosanguineous fluid. The chest surfaces were covered by firm whitish nodules up to 6 × 5 × 3 mm.
  • On microscopy the tumour cells were predominantly spindle-shaped, and the preliminary diagnosis was fibrosarcoma.
  • Tumour cells expressed both cytokeratin and vimentin. This led to a final diagnosis of predominantly fibrous malignant mesothelioma.
  • Signs of malignancy were invasive growth and spread to the sternal lymph node and the lung.
  • A separate 7 × 7 × 6 mm nodule in the right caudal lung lobe was a pulmonary adenocarcinoma of the acinar type.
• The authors' conclusion: The authors concluded that mesothelioma should be considered as a possible diagnosis in cats with dyspnoea, thoracic effusions and pleural thickening. They also concluded that immunohistochemistry should be included in diagnosis, because the subtypes can be mistaken for carcinomas or sarcomas.
• Limitations the authors state:
  • Clinical diagnostic tests before death were hindered by the cat's behaviour.

Topics

Medical terms in this study, explained in our Lexicon: Mesothelioma, Neoplasm, Immunohistochemistry.

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