Tumors, also called neoplasms, are abnormal masses of tissue created by uncontrolled cell division that serve no physiological purpose. A tumor can be benign or malignant. Benign tumors are autonomous, nonlethal, and grow more slowly than malignant ones. Malignant tumors are cancerous growths that spread rapidly and can metastasize or spread to other areas of the body.
Malignant tumors grow by invading nearby cells and spread to other parts of the body through a process called metastasis . The cells break away from the tumor, enter the bloodstream or lymphatic system, and spread to another area, infecting additional tissue. This is how a tumor that starts in one part of the body, like the breast or prostate, can spread to another type of tissue, like the bone.
If there is a suspicious tumor, it is common for a doctor to biopsy or cut out a small sample of the tumor, which is then examined under a microscope. The cells in malignant tumors are different from normal cells in several ways. Normal cells have a uniform shape with a nucleus containing chromatin and a nucleus containing RNA and DNA. Malignant tumors have irregular cells with large irregular nucleoli and chromatin. Also, malignant cells do not stick together like normal cells and stain differently under a microscope.
The TNM classification system designed by the International Union Against Cancer attempts to classify malignant tumors based on the extent to which they have spread throughout the body. The T represents the size of the tumor, the N represents any lymph nodes that may be involved, and the M represents the extent of metastasis, or the extent of the cancer throughout the body. This method is used for lung, colon, and stomach cancers, among others.
Brain and spinal tumors use a classification method ratified by the World Health Organization that is based on the premise that the different types of malignant tumors of the nervous system are the result of abnormal growth of specific types of cells. In this system, the tumor is classified according to the type of cell it resembles. Once the tumor is graded, it is assigned a numerical grade that indicates the degree of malignancy. The more aggressive the tumor, the higher the assigned number.
Symptoms vary depending on the type and location of the mass, and some malignancies have no symptoms until the cancer reaches the most aggressive stage. Colon cancer symptoms include diarrhea, constipation, bleeding, and anemia, while lung cancer is accompanied by cough, shortness of breath, and chest pains. Fatigue, pain, fever, loss of appetite, and weight loss are also symptoms of various malignancies. In addition to a biopsy, other diagnostic tools include blood tests, magnetic resonance imaging (MRI), x-rays, computed tomography (CT), and positron emission tomography (PET).
Treatment of malignant tumors depends on the type of cancer, the location of the tumor, and the degree of mastitis, among other factors. Whenever possible, surgical removal is recommended to prevent further spread of the disease. If the tumor has not spread, further treatment may not be necessary. If the spread is limited to a few lymph nodes, they are also removed. Certain types of cancer or those that have spread to other areas of the body often require radiation, chemotherapy, or a combination of the two.