Mesothelial cells of peritoneal fluid

Area of Science:

• Veterinary cytology
• Equine internal medicine
• Cellular pathology

Background:

• Mesothelial cells line the peritoneal cavity and can change appearance in response to inflammation.
• Distinguishing normal from reactive mesothelial cells is important for accurate diagnosis in horses.

Purpose of the Study:

• To characterize the morphological differences between normal, activated, and transformed equine mesothelial cells in peritoneal fluid.
• To provide diagnostic criteria for identifying reactive mesothelial cells in equine cytology.

Main Methods:

• Examination of Giemsa-stained peritoneal fluid cytology preparations from 159 horses using light microscopy.
• Detailed morphological analysis of mesothelial cell nuclear and cytoplasmic features.

Main Results:

• Normal mesothelial cells exhibit oval nuclei and pale blue cytoplasm.
• Activated mesothelial cells show pleomorphism and intense basophilia, potentially mimicking neoplasia.
• Transformed mesothelial cells in chronic inflammation may be phagocytic with cytoplasmic vacuolation.

Conclusions:

• Morphological assessment of mesothelial cells in equine peritoneal fluid aids in differentiating inflammatory conditions.
• Recognizing activated and transformed mesothelial cell features is key to avoiding misdiagnosis of neoplasia.