Wright's stain, 500x

Mesothelial cells are part of the serous membrane, which covers the thoracic and abdominal organs. These cells have a rounded shape and can exfoliate in large numbers if the serous membrane is irritated. They are characterized by a cellular outline that possesses fine undulations, referred to as their “crown”. Mesothelial cells can transform and become phagocytes, which will cause them to acquire vacuoles in their cytoplasm. They can also become multinucleated when they are activated.