A neoplasm is an abnormal growth of tissue that forms when cells begin to multiply and divide in ways they should not. These growths can develop anywhere in the body, from the skin to internal organs, and range from harmless masses to life-threatening cancers. Understanding what neoplasms are, how they develop, and what can be done about them is an important step in protecting your health and making informed decisions about your care.

Understanding Neoplasms: What They Are

The word neoplasm comes from ancient Greek words meaning “new formation.” It refers to any mass of tissue that grows abnormally and continues growing even after the original trigger that started it is removed. Your body is constantly making new cells to replace old or damaged ones that die off. This process usually works smoothly, with cells growing, dividing, and dying in a carefully controlled way. But sometimes this system breaks down. When cells don’t die off as expected, or when new cells grow and multiply faster than they should, they pile up and form a mass. This mass is what we call a neoplasm or tumor.^[1]

Not all neoplasms are the same. The term “neoplasm” is a broad one that includes both benign (noncancerous) and malignant (cancerous) growths. A benign neoplasm is one that stays in one place, grows slowly, and doesn’t spread to other parts of the body. Even though the cells in these growths are abnormal, they are usually well-organized when examined under a microscope. Most benign neoplasms are not life-threatening, though they can cause problems if they press on nearby organs or tissues. Examples include uterine fibroids, skin moles, and fatty lumps under the skin called lipomas.^[4]

Malignant neoplasms, on the other hand, are cancerous. These tumors grow rapidly, invade nearby tissues, and can spread to distant parts of the body through the bloodstream or lymphatic system—a process called metastasis. Malignant neoplasms are dangerous because they disrupt normal body functions, destroy healthy tissue, and can be fatal if not treated. There is also a third category called precancerous or premalignant neoplasms. These are abnormal growths that are not yet cancer but have the potential to become malignant over time if left untreated.^[6]

Epidemiology: How Common Are Neoplasms?

Cancer, which is the result of malignant neoplasms, has become one of the most significant public health challenges worldwide. Every day, more than 52,900 people are diagnosed with cancer, and over 27,000 people die from it. By the year 2040, experts estimate there will be 28 million new cancer cases and 16.2 million deaths globally.^[15]

Malignant neoplasms are most likely to affect people over the age of 65, though they can occur in people of all ages. This means that as populations around the world age, the burden of cancer is expected to increase. However, it’s important to remember that not all neoplasms are malignant. Benign tumors are quite common and occur in people of all ages. Many people live with benign neoplasms without ever experiencing serious health problems.^[1]

Causes: Why Do Neoplasms Form?

Neoplasms form when cells grow and divide faster than they should. But why does this happen? The answer often lies in changes, or mutations, in the DNA of cells. DNA is like an instruction manual that tells cells how to grow, divide, and die. When mutations occur in key genes that regulate these processes, cells can lose their normal controls and begin to multiply out of control.^[7]

These mutations can happen for several reasons. Sometimes they occur spontaneously, with no clear cause. Other times they are triggered by external factors. For example, exposure to radiation, tobacco smoke, air pollutants, or industrial chemicals can damage DNA and lead to the development of neoplasms over time. Infectious agents also play a role in some cancers. Human papillomavirus (HPV) is strongly linked to cervical and throat cancers, hepatitis B and C viruses are associated with liver cancer, and Helicobacter pylori infection can lead to stomach cancer.^[7]

In some cases, genetic mutations that increase the risk of developing neoplasms are inherited from parents. For example, mutations in the BRCA1 and BRCA2 genes significantly raise the risk of breast and ovarian cancer. People with these inherited mutations don’t automatically develop cancer, but they have a much higher chance of doing so compared to the general population. Hormonal imbalances and chronic inflammation—such as in inflammatory bowel disease—can also create conditions that promote abnormal cell growth.^[5]

Even though scientists understand many of the factors that contribute to neoplasm formation, experts still don’t fully understand why some people develop them while others don’t, even when exposed to the same risk factors.^[1]

Risk Factors: Who Is More Likely to Develop Neoplasms?

Certain groups of people, behaviors, and habits increase the risk of developing neoplasms, particularly malignant ones. Age is one of the most significant risk factors. The risk of cancer increases as people get older, with the majority of malignant neoplasms occurring in people over 65. This is partly because DNA damage accumulates over time, and the body’s ability to repair damaged cells decreases with age.^[1]

Lifestyle factors also play a major role. Smoking tobacco is one of the leading causes of cancer, linked to lung, throat, mouth, and many other types of cancer. A poor diet, obesity, lack of physical activity, and excessive alcohol consumption all increase cancer risk. These factors often interact with each other and with genetic predispositions to accelerate cellular changes that lead to neoplasms.^[7]

People with a family history of cancer or inherited genetic conditions are at higher risk. If close relatives have had certain cancers, particularly at a young age, it may indicate an inherited genetic mutation that increases cancer risk. Environmental exposures are another important factor. People who work with certain chemicals, are exposed to high levels of radiation, or live in areas with heavy air pollution face a higher risk of developing neoplasms.^[5]

Symptoms: How Do Neoplasms Affect the Body?

The symptoms of a neoplasm vary greatly depending on where it is located, how large it is, and whether it is benign or malignant. In some cases, you might be able to feel a lump or bump under the skin. For example, a breast lump might be detected during self-examination, or a swelling might be noticed in the neck, underarm, or groin area. Some neoplasms near the skin’s surface appear as raised, abnormal areas or sores.^[5]

However, many neoplasms cannot be felt or seen from the outside. Internal tumors often cause symptoms related to their location. Someone with a neoplasm in the colon might notice changes in bowel habits, abdominal pain, or blood in their stool. A person with a neoplasm in the breast might experience breast pain or abnormal nipple discharge. Those with neoplasms in the lungs might have a persistent cough, shortness of breath, or chest pain.^[1]

There are also general symptoms that people with neoplasms, especially malignant ones, may experience. These include unexplained weight loss, persistent fatigue, fever or chills, night sweats, loss of appetite, and unusual bleeding. Some people may notice changes in their skin, persistent pain, or difficulty swallowing. It’s important to remember that many of these symptoms can be caused by conditions other than neoplasms. However, if you experience any persistent or unusual symptoms, it’s important to see a healthcare provider for evaluation.^[5]

Prevention: Can Neoplasms Be Prevented?

While not all neoplasms can be prevented, there are many steps you can take to reduce your risk, especially for malignant neoplasms. One of the most important things you can do is avoid tobacco in all forms. Smoking is the leading preventable cause of cancer and is linked to many types of malignant neoplasms. If you smoke, quitting is one of the best decisions you can make for your health. Even if you don’t smoke, avoiding secondhand smoke is also important.^[1]

Maintaining a healthy lifestyle can significantly reduce cancer risk. This includes eating a diet rich in fruits and vegetables, maintaining a healthy weight, staying physically active, and limiting alcohol consumption. Regular exercise has been shown to lower the risk of several types of cancer and can also improve overall health and well-being. Protecting your skin from excessive sun exposure and avoiding tanning beds helps prevent skin cancer.^[1]

Vaccinations can prevent some cancers caused by infections. The HPV vaccine protects against the viruses that cause most cervical, throat, and other cancers. The hepatitis B vaccine helps prevent liver cancer. Regular cancer screenings are also a crucial part of prevention. Screenings can detect precancerous changes before they become malignant or find cancer at an early stage when it is most treatable. Examples include mammograms for breast cancer, colonoscopies for colorectal cancer, Pap tests for cervical cancer, and low-dose CT scans for lung cancer in high-risk individuals.^[7]

If you have a family history of cancer or known genetic mutations that increase cancer risk, genetic counseling and testing may be helpful. This can provide information about your personal risk and guide decisions about preventive measures, such as increased screening or preventive surgeries in some cases.^[5]

Pathophysiology: How Neoplasms Change Normal Body Functions

Understanding how neoplasms affect the body requires looking at what happens at the cellular level. In a healthy body, cells follow a strict life cycle. They grow, divide to create new cells, and die in a controlled process called apoptosis. The body has multiple systems in place to ensure this process stays balanced. Special genes called tumor suppressor genes act like brakes, stopping cells from dividing too quickly. Other genes called oncogenes act like accelerators, promoting cell division when needed.^[6]

When mutations occur in these genes, the careful balance is disrupted. If tumor suppressor genes are damaged, the brakes fail, and cells keep dividing even when they shouldn’t. If oncogenes become overactive, the accelerator gets stuck, and cells divide uncontrollably. Normally, the body’s immune system identifies and destroys abnormal cells before they can cause problems. But cancer cells have developed ways to evade the immune system, allowing them to grow unchecked.^[6]

Benign neoplasms grow slowly and remain localized. They push aside normal tissue but don’t invade it. While they can cause problems by pressing on nearby organs or structures, they generally don’t disrupt the body’s overall function. Malignant neoplasms, however, behave very differently. They grow rapidly and invade surrounding tissues, destroying normal structures as they expand. As they grow, malignant cells can break away from the original tumor and travel through the bloodstream or lymphatic system to distant parts of the body, forming new tumors called metastases. This ability to spread is what makes malignant neoplasms so dangerous.^[4]

Malignant neoplasms also affect the body in other ways. They can cause bleeding, block important structures like the intestines or airways, and interfere with organ function. Some tumors produce hormones or other substances that cause symptoms throughout the body. As cancer progresses, it can lead to weight loss, fatigue, and a general decline in health—a condition called cachexia. Understanding these mechanisms helps doctors develop better treatments and strategies to manage neoplasms.^[1]

Types of Malignant Neoplasms

Malignant neoplasms, or cancers, are classified into several main types based on where they originate in the body. Carcinomas are by far the most common, making up about 90% of all cancer cases. These cancers begin in epithelial tissue, which is the tissue that lines the skin and the inside of organs. Common carcinomas include cancers of the skin, breast, prostate, bladder, cervix, lung, colon, and rectum.^[1]

Sarcomas are cancers that begin in connective tissues like bones, cartilage, muscle, tendons, and fat. Unlike many other types of cancer, sarcomas are more common in young adults. The most common type is soft tissue sarcoma. Myelomas, also called multiple myeloma, form in plasma cells, which are immune cells found in bone marrow. Leukemias, often called blood cancers, are cancers of the bone marrow that lead to the overproduction of immature blood cells. This causes problems like anemia, fatigue, and bleeding disorders.^[1]

Lymphomas are cancers that develop in the lymphatic system, particularly in the glands or nodes. These can occur anywhere in the body but are most commonly felt as lumps in the neck, underarm, or groin areas. Sometimes, malignant neoplasms can spread to the brain from other parts of the body. The most common cancers that spread to the brain include breast, skin (melanoma), lung, colon, and kidney cancers, though this is relatively rare, affecting less than 1% of the population.^[1]