Definition of Tumor
A tumor is an abnormal growth of body tissue. Tumors can be cancerous (malignant) or noncancerous (benign).
Causes, incidence, and risk factors
In general, tumors occur when cells divide excessively in the body. Typically, cell division is strictly controlled. New cells are created to replace older ones or to perform new functions. Cells that are damaged or no longer needed die to make room for healthy replacements.
Symptoms depend on the type and location of the tumor. For example, lung tumors may cause coughing, shortness of breath, or chest pain. Tumors of the colon can cause weight loss, diarrhea, constipation, iron deficiency anemia, and blood in the stool.
Signs and tests
Like the symptoms, the signs of tumors vary based on their site and type. Some tumors are obvious, such as skin cancer. However, most cancers cannot be seen during an exam because they are deep inside the body.
Treatment varies based on:
The outlook varies greatly for different types of tumors. If the tumor is benign, the outlook is generally very good. However, there are some instances where a benign tumor can cause significant problems, such as in the brain.
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc. – 8/14/2010