Lung cancer can form within the air sacs or within the airways that carry air into the lungs. As the cancer progresses, the cancer eventually spreads throughout the lung tissue and leads to a buildup of fluid around the heart and lungs, called a pleural effusion. This fluid often serves to help the spread of cancer, and may contain a number of types of cells depending on the type of lung cancer involved.
Adenocarcinoma Cells
Malignant fluid around the heart may contain adenocarcinoma cells--cancer cells that develop from within the glandular tissues of the lungs. Adenocarcinoma of the lungs is a type of non-small cell lung cancer--a group of cancers that account for up to 87 percent of lung cancer cases, according to the Merck Manuals. Adenocarcinoma cells arise from the airways of the lungs and may have the ability to secrete compounds such as mucous. Patients with adenocarcinoma cells in the fluid around the heart require immediate cancer treatment, such as chemotherapy or radiation, to slow or stop cancer spreading.
Oat Cell Cancer Cells
In other cases, patients with oat cell cancer may have oat cells in the fluid around the heart or lungs. Oat cell cancer is one of two forms of small cell lung cancer, and it is most commonly caused by exposure to cigarette smoke, asbestos or radon, according to the National Cancer Institute. Doctors can identify oat cells in the fluid around the heart by the cell's appearance, since oat cells are relatively small and appear similar to rolled oats. Patients with oat cell cancer that has spread to the fluid around the heart and lungs must undergo cancer therapy, including chemotherapy, radiation or experimental treatments.
Squamous Cells
Other cells that may be found in the fluid around the heart and lungs are squamous cells. Squamous cell lung cancer is another form of non-small cell lung cancer and presents the second most common form of lung cancer, according to VirtualMedicalCenter.com. The cancer develops from the squamous cells in the air sacs of the lungs that normally function to allow gas transfer from the air into the bloodstream. Doctors can identify squamous cell carcinoma cells in the pleural by examining the fluid under a microscope--the cells will have a flattened appearance. Once identified, patients with invasive squamous cell carcinoma of the lung require aggressive cancer therapy.
