Mesothelioma

Peritoneal mesothelioma (Image sourced from BioMed Image Archive with permission)

Peritoneal

• Mesotheliomas
  • Malignant - implantation rather than metastasis
  • Mainly cattle and dogs, occasionally in other species
  • Can be congenital in calves
  • Arise from serosa of pericardial, pleural and peritoneal cavities
  • Multiple small nodules, may be pedunculated, few milimeters to few centemeters, may present as villous projections
  • May be associated with milky or bloody effusions
  • Histologically usually appear similar to adenocarcinoma (papillary) or fibrosarcoma (spindle cells)

Image of glandular type mesothelioma in a cat from Cornell Veterinary Medicine

Pleural

• Has been found in cat, dog, cow, goat and horse
• Arise from pericardial, pleural and peritoneal surfaces
• May be related to inhalation of asbestos
• Grossly:
  • Multiple discrete nodules
• Microscopically:
  • Can appear as a carcinoma or fibrosarcoma depending on which tissue, covering or supporting, is predominant in the neoplasm
• Rarely metastasise but are considered malignant