Mesothelioma of the pleural cavity in a horse: diagnostic features

Diagnostic dichotomy: A question of thoracic mesothelioma

“…In particular, it may be difficult to Thoracic mesothelioma distinguish between reactive mesothelial cells and neoplastic cells associated with malignant mesothelioma and adenocarcinoma (Kramer et al 1976;Addis and Roche 2009). The most consistently reported features of pleural fluid cytology in equine mesothelioma cases include pleomorphic mesothelial cells forming sheets or clumps, with multiple nuclei, anisokaryosis and mitotic figures; histological examination of tissue samples shows fibrous pleural stroma with reactive mesothelium, granulation tissue, necrotic foci and clumps of pleomorphic cells (Kramer et al 1976;Mair et al 1992;Mair and Brown 1993;Fry et al 2003;Stoica et al 2004;Dobromylskyj et al 2011). Unfortunately, cellular changes or neoplastic cells may not always be observed in effusions (Kramer et al 1976;Stoica et al 2004).…”

“…It arises from the single layer of mesothelial cells that line the peritoneal, pleural or pericardial cavities. Only a limited number of case reports of equine mesothelioma have been published (Straub et al 1974;Kramer et al 1976;Ricketts and Peace 1976;Carnine et al 1977;Kolbl 1979;Wallace et al 1987;Colbourne et al 1992;Mair et al 1992;Harps et al 1996;Fry et al 2003;Stoica et al 2004). In man, this neoplasm is strongly associated with asbestos exposure (Brenner et al 1982); however, there is little clinical evidence for this in animals, although one author associated airborne fibres with mesothelioma in 6 urban-dwelling dogs (Harbison and Godleski 1983).…”

“…Cytological analysis of effusions and histopathological evaluation of representative tissue biopsies are used to make a diagnosis. However, difficulty in reaching a definitive diagnosis can arise due to problems in differentiating between reactive and neoplastic mesothelial cells in cytological and histopathological preparations (Kramer et al 1976;Mair et al 2004;Addis and Roche 2009;Davis and Rush 2013) and, as such, only 3 case reports describe ante mortem diagnosis of mesothelioma in horses (Kramer et al 1976;Mair et al 1992;Fry et al 2003). The rapid progression of the disease and the grave prognosis associated with mesothelioma mean that euthanasia often precedes accurate diagnosis.…”

Metastatic sclerosing mesothelioma in a cow

“…2 In one study conducted over an 18-year period, only eight beef cattle were diagnosed with mesothelioma. 10 In many species including cat, 1,11 dog 6,12 and horse, 13 adult animals are generally affected, whereas in bovines mesothelioma occurs in both adults 8,14-16 and calves. [17][18][19] In our case report, mesothelioma was diagnosed in a 7-yearold cow, suggesting an acquired, rather than a congenital, mesothelioma.…”

Tumour necrosis factor ‐ physiology and pathology

“…In their discussion in the accompanying article (p 59), Mair, Hillyer and Brown (1992) Evidence for this protective function of TNF in experimental animals is starting to accumulate. A monoclonal antibody to murine TNF lead to death in mice suffering from experimental peritonitis following caecal ligation, a process that was otherwise sub-lethal.…”