Cells are the basic building blocks of all living organisms. In a healthy body, cells follow an orderly life cycle: they develop from a systematic process called mitosis, perform important physiological functions to maintain body homeostasis (i.e., a stable internal environment), and die via apoptosis when they become dysfunctional, old, or no longer needed. This cycle is tightly regulated by DNA – the body’s genetic code that controls when and how each cell functions.
With about 30 trillion cells in each human body, some cells naturally develop mutations in their genetic code that disrupt their life cycle. Mutations can be caused by genetic issues, environmental exposures (e.g., tobacco smoke, radiation), infections, lifestyle, and other etiologies. Cells with mutated genetic codes are usually detected and removed by the body’s immune system, or they stop working and die on their own. However, sometimes these altered cells survive and gain a competitive growth advantage, causing them to replicate more rapidly than normal. Over time, this uncontrolled growth can create a mass of cells known as a tumor.
Tumors can develop anywhere cells are present (i.e., essentially anywhere in the body), and they are classified as benign or malignant. Benign tumors are non-cancerous, and they typically grow slowly and exhibit clear boundaries. Contrariwise, malignant tumors are invasive to nearby tissues – a hallmark of cancer – and are characteristically more aggressive. A biopsy is often necessary to confirm whether a tumor is benign or malignant. Notably, not all tumors are cancer (e.g., a benign tumor is not cancer), and not all cancers produce tumors (e.g., leukemia is a cancer of the blood).
A serious feature of malignant cancers is their ability to spread to other locations in the body – a process known as metastasis. Metastasis occurs when malignant cells break away from the original tumor, travel through the bloodstream or lymphatic system (or other pathway), and seed new tumors in other areas of the body. This makes cancer more difficult to treat and can provoke additional sequelae.
Clinical jargon associated with tumors and cancer can be daunting, but breaking down the terminology can be helpful. For example, the root words “hem-” means blood, “angio-” means vessel, and “-oma” means tumor, so a “hemangioma” is quite literally a “blood vessel tumor”. Additional terminology can be descriptive; for example, a “giant intramuscular lipoma” describes a fatty (“lyp-”) tumor (“-oma”) that is located within (“intra-”) a muscle (“-muscular”) and is at least five centimeters in any one dimension (the criteria for “giant” classification).
While loss of control is the foundational concept for tumor and cancer development, routine screening, avoiding carcinogens, and other controllable actions are important for preventing cancer, detecting it in early stages, and performing early interventional treatment. A lump, bump, or lesion might be just that, or it might be something serious. Tumors and cancer are complex, and they command respect and proper attention. It’s important to consult a physician about such concerns so they can execute a proper workup and assemble a multi-disciplinary healthcare team as warranted.
Richard P. Holm, MD passed away in March 2020 after a battle with pancreatic cancer. He is founder of The Prairie Doc®. For free and easy access to the entire Prairie Doc® ® library, visit www.prairiedoc.org and follow Prairie Doc® on Facebook. Ethan L. Snow, PhD, MA is a clinical anatomist who currently serves as an Associate Professor at South Dakota State University in Brookings, South Dakota.
