Epithelium is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is the cellular covering of all of the internal and external surfaces of the body, protecting the organs, inner cavities and outer surfaces of the body in a continuous layer of multi-layered tissue. Squamous cells are flat, scale-like cells that form the outer layer of skin. An squamous epithelium is a type of epithelium that consist of outer layer of squamous cells. A malignant tumor that arises from squamous epithelium in lungs is known as squamous cell carcinoma of the lung.
This rare form of primary tumor in dogs is highly metastatic in nature, spreads rapidly to other parts of the body specially if it reaches the regional lymph nodes.
Early on, squamous cell lung cancer may have no symptoms. If symptoms occur, they may include
Coughing up blood and mucus
hypercalcemia (high levels of calcium)