A neoplasm is an abnormal tissue mass that forms when cells grow and divide more than they should or do not die when they should. It can also be referred to as a tumor. Sometimes, they are benign (noncancerous), and sometimes they are malignant (cancerous), causing medical complications and even death.
Lung neoplasms are tumors that form either from lung tissue, also known as a primary neoplasm, or from the distant spread of cancer from another part of the body, also known as metastatic neoplasms of the lung.
This article will look at the different types of lung neoplasms, as well as causes and treatment options.
Definition of Lung Neoplasm
It’s easy to think “cancer” when you hear the terms “lung neoplasm” or “tumor,” but many times that is not the case. Although the words “lung neoplasm” may sound ominous, these growths aren’t always a cause for concern.
A benign lung neoplasm is a harmless nodule or mass that occurs anywhere in the lungs, and can usually be followed for growth over a period of months or years. These tumors require only observation with a routine chest X-ray or computed tomography (CT) scan to see if they change in shape or size.
A malignant neoplasm, or lung cancer, is much more concerning. It requires immediate attention. Malignant lung neoplasms are characterized by abnormal-looking cells that divide uncontrollably, leading to tumors in the lungs (primary neoplasms) that may spread to other parts of the body (metastatic neoplasm).
Types of Lung Neoplasms
Benign lung neoplasms are noncancerous and are usually classified by the tissues from which they arise. Benign lung neoplasms include:
- Hamartomas: Hamartomas are the most common type of benign lung nodule, accounting for about 55% of all benign lung tumors. They are unique in that these tumors consist of a variety of cell types, including muscle, fat, and cartilage. They are most often found on the periphery of the lung, along the outer edges. These coin-shaped tumors are usually small in size, oftentimes measuring 4 centimeters or less in diameter, and are commonly found accidentally on an X-ray.
- Bronchial adenomas: These neoplasms arise from the mucus glands or ducts of your windpipe or the large airways of the lungs. They are slow growing and rarely become malignant. Some types of bronchial adenomas are more common than others. For example, carcinoids (tumors made up of neuroendocrine cells) account for 85% of bronchial adenomas (and 1%–2% of all lung cancers due to malignant transformation).
- Papillomas: Arising from salivary glands, these are the least common type of benign lung neoplasm. They usually grow in the bronchial tubes. The two most common types of papillomas are squamous and glandular. Squamous papillomas are the result of the human papilloma virus (HPV). The cause of glandular papillomas remains a mystery.
Malignant lung neoplasms are cancerous and include three main types:
- Small-cell carcinoma (SCLC): SCLC makes up 10%–15% of all lung cancers. Almost all cases of small cell lung cancer are due to cigarette smoking. There are two types of this aggressive form of lung cancer: small cell carcinoma (with the most common subtype being oat cell cancer) and combined small cell carcinoma. These fast-growing cancers are extremely lethal. In fact, at the time of diagnosis, about 70% of SCLC patients have metastatic spread of their cancer, with radiation and chemotherapy providing little relief.
- Non-small cell carcinoma (NSCLC): This is the most common type of malignant lung neoplasm, making up 80%–85% of all lung cancers. Current and former smokers may develop this type of cancer while smoking or years after quitting. Most nonsmoking related lung cancers also fall in this category. There are three main types: adenocarcinoma (the most common type of lung cancer in the United States), large cell carcinomas (can appear anywhere in the lungs), and squamous cell carcinomas (often associated with smoking).
- Mesothelioma: Mesothelioma is a rare cancer of the chest lining that is most often caused by long periods of asbestos exposure (about 30–50 years) in the home or workplace. It accounts for about 5% of all lung cancer cases.
Other lung tumors that may affect the lungs include lymphomas, adenoid cystic carcinomas, and sarcomas. These types of cancer are treated differently than the more common lung cancers.
Mediastinal tumors (growths that form in the chest area between the lungs) and other chest wall tumors, such as sarcomas, are rare tumors that do not develop in the lungs but may spread there due to their closeness to the organ.
The following cancers start elsewhere and commonly spread to the lungs:
Cancers that spread from one site to the lungs are not considered lung cancer, therefore treatment should be targeted toward the area of the body where the cancer originally developed.
Lung neoplasm can be benign or cancerous. There are three main types of benign tumors: hamartomas, bronchial adenomas, and papilloma. These tumors can often be left untreated, only needing to be monitored for growth regularly.
Cancerous lung neoplasms, on the other hand, require immediate medical attention and treatment, as many are fast growing and aggressive. Types of malignant lung neoplasms include small cell carcinoma, non-small cell carcinoma, and mesothelioma.
Causes of Lung Neoplasms
Smoking in any form, including traditional cigarettes, hookah, snuff, cigars, and pipe tobacco, is the single biggest risk factor for lung neoplasms. The 60 or so carcinogens, or cancer-causing chemicals, in tobacco smoke account for more than 80%–90% of lung cancer cases.
Research shows that smokers are 15–30 times more likely to get lung cancer or die from lung cancer than nonsmokers. Your risk of developing lung cancer increases proportionally with the number of cigarettes you smoke in your lifetime.
Smoking isn’t the only cause of lung neoplasms. Benign lung neoplasms can develop from an abscess, inflamed tissue, or cysts or as a result of scarring from an infection or pneumonia. Other causes of lung neoplasms are:
- A history of radiation therapy (usually during treatment for another type of cancer)
- Exposure to asbestos, radon gas, or other carcinogens like heavy metals and diesel exhaust
- Exposure to industrial chemicals in the workplace, such as arsenic, nickel, silica, and chromium
- Genetic alterations and hereditary conditions
- Secondhand smoke exposure
- Air pollution
Sometimes, genetics may predispose you to lung cancer. This is more likely the case in individuals with an immediate nonsmoking family member who has or had lung cancer.
Familial forms of lung cancer may be influenced by several nongenetic factors, including similar lifestyles, such as diet and exercise, and similar environments, like living in areas with high levels of indoor and outdoor air pollution.
Quitting smoking, moving out of a high pollution area or job, and living a generally healthy life that includes eating right and exercising are ways to decrease your lung cancer risk, even if you are at higher risk based on your genetic profile.
Smoking is the biggest risk factor for developing a lung neoplasm. Other risk factors include lung infections, exposure to radiation, exposure to industrial chemicals, exposure to air pollution, secondhand smoke, and a genetic predisposition.
How a Lung Neoplasm Is Diagnosed
If you have ongoing respiratory symptoms (such as a persistent cough, recurrent respiratory infections, wheezing, and shortness of breath) that suggest a lung neoplasm, your healthcare provider may start by taking a detailed medical history.
Your healthcare provider will perform a focused physical exam, listening to the heart and lungs for sounds like wheezing and crackling that may be concerning for associated lung-related diseases, like COPD and emphysema, which increase one’s chances of malignancy.
Imaging is usually ordered next. The following tests are initially performed to help provide more details on the lung neoplasm:
- Chest X-ray: This test is usually the quickest and least expensive imaging test, so it is used first. It is a painless scan that can show tumors 1 centimeter wide or larger.
- CT scan: CT scans use low-radiation X-ray beams to take many pictures of the inside of your body. They can help detect smaller lung cancers and provide more details than an X-ray.
- Lung function test (LFT): Also known as spirometry, this test measures how much air the lungs can hold and how quickly the lungs can be filled with air and then emptied.
- Blood tests. A sample of your blood may be tested to check the number of red blood cells, white blood cells, and platelets (full blood count), and to see how well your kidneys and liver are working. Because lung cancer can throw off these numbers, comparing your baseline numbers to your current numbers can help provide details on potential changes that have occurred as a result of your lung cancer.
Former Smokers Need Regular Screening
If you were a regular smoker who has quit, a heightened risk of developing cancer remains for 15 years after quitting. In this group, periodic lung cancer screening with low-dose CT is encouraged during this period. This aids in catching any potential cancerous lung neoplasms that may develop at the earliest stage possible and improves outlook.
If imaging shows nodules, or if you have risk factors such as a prior history of smoking or a nonsmoking first relative with lung cancer, a pulmonologist (a doctor who specializes in the diagnosis and treatment of lung-related illness) may also suggest a bronchoscopy. In this procedure, a doctor places a scope with a built-in camera into a sedated patient’s mouth, down the airway, and into the lungs to examine the lung nodule.
During this procedure, your doctor will usually conduct a biopsy. This procedure involves extracting a piece of tissue from the lung, which is then sent to a lab to be tested and examined under a microscope.
Biopsy results will confirm whether the lung neoplasm is benign or malignant (cancerous), and additional tests may be done on the tissue sample to determine the type of lung cancer and the best course of treatment.
Many lung neoplasms are found incidentally during imaging tests for another condition. If a lung neoplasm is suspected, your healthcare provider will take a detailed medical history, do a physical exam, and order imaging tests, such as a chest X-ray or CT scan. Testing of phlegm, or mucus, that has been coughed up or a biopsy may also be done.
Treatment for a Lung Neoplasm
Whether your lung neoplasm is benign or malignant plays an important role in your treatment. In people with no symptoms, an abnormal nodule or mass on the lung is sometimes found incidentally on a chest X-ray or CT scan while looking for something else.
In many cases, your healthcare provider will advise monitoring a benign neoplasm without immediate treatment, what is known colloquially as a “watch and wait” method. This method of monitoring potentially benign nodules is reserved for those who have little or no risk factors for lung cancer and are otherwise generally healthy.
If imaging or a biopsy confirm the lung neoplasm to be cancerous, then the type of treatment you receive will depend on several factors:
- The type of lung cancer you have (non-small cell lung cancer, NSCLC, vs. small cell lung cancer, SCLC)
- The size, position, and location of the cancer
- How advanced your cancer is (the stage)
- Your overall health
The types of treatments for lung cancer largely depend on whether you have NSCLC or SCLC and how far the cancer has spread. Your options will usually include one or more of the following:
Chemotherapy is a systemic treatment used to kill rapidly dividing cells. It can be administered orally or intravenously (through IV) and used prior to surgery (neoadjuvant chemotherapy) or afterward (adjuvant chemotherapy).
As a class, NSCLCs are usually less sensitive to chemotherapy and radiation therapy compared to SCLC, although people with resectable lung neoplasms may be cured by surgery or surgery followed by chemotherapy.
The goal of chemotherapy is to:
- Achieve remission and cure
- Stopping the spread of cancer in its tracks
- Relieve symptoms by shrinking the tumor, thereby increasing one’s quality of life
- Help other treatments—by reducing the size of tumors via neoadjuvant therapy surgery is made more effective and at times curative
- Stop cancer from coming back—maintenance chemotherapy can help achieve remission
By using a controlled dose of radiation (high-energy beams), cancer cells can be killed or damaged, eliminating any remaining cancer cells after surgery and chemotherapy. Some cancers like NSCLCs are less sensitive to radiation so accurate diagnosis is critical to choosing the best and most effective treatments for you.
If you have NSCLC in one lobe, a lobectomy, or surgery to remove cancer cells in one lobe, may be an option, and possibly curative if you are in good health. Depending on the stage of your cancer, surgery may be followed by a course of chemotherapy to destroy any cancer cells that may have remained in your body.
Surgery isn’t usually used to treat SLCL because the cancer has often already spread to other areas of the body by the time it’s diagnosed. In these cases, the use of chemotherapy, radiation, and even immunotherapy have proven to be a more effective course of action.
In patients with cancer that is localized to the middle lobe or entire lung but has yet to metastasize, a pneumonectomy (the removal of an entire lung) or a wedge resection (the removal of a small piece of the lung) may be performed. Chemoradiation (having chemo and radiation at the same time) after surgery is often used on these patients no matter whether they have SCLC or NSCLC.
Immunotherapy is a group of medicines that jump-starts your immune system to target and kill cancer cells. It is more commonly used to treat small cell lung cancer.
Currently, two immunotherapy treatments are used for lung cancer are Keytruda (pembrolizumab) and Tecentriq (atezolizumab). They can be used alone as a primary form of treatment or combined with chemotherapy.
If you receive a diagnosis of lung cancer, you can feel a wave of emotions. Because of the high rate of malignancy and rapid progression of some lung cancers, it is natural to feel like you do not have time to adjust to the mental, emotional, and physical changes that are taking place.
Assembling a team, joining a support group, discussing how you feel with family and friends, and learning how to manage your symptoms of shortness of breath and treatment side effects may be helpful coping strategies. Using alternative remedies such as acupuncture, yoga, hypnosis, therapy, and meditation may also have some benefits in navigating the complex emotions that come with this life-altering diagnosis.
Still, despite a healthcare team’s best efforts, sometimes treatments don’t work. Knowing exactly when to start discussing palliative care (relieving symptoms) can be difficult. Research has shown that starting palliative care for those with advanced lung cancer mproves quality of life and decrease the psychological burden.
Lung neoplasms are abnormal growths of tissue that form in the lungs. Many are benign (noncancerous) but some may be malignant (cancerous). If a lung neoplasm is suspected to be cancerous, your healthcare provider may recommend imaging tests, a biopsy, and other tests. Lung cancer is usually treated with surgery, chemotherapy, radiation, and immunotherapy, or some combination of those options.
A Word From Verywell
Most lung neoplasms are no cause for worry, but they should all be checked by a healthcare professional, such as an oncologist (cancer specialist), pathologist (doctor who examines tissues in a lab), and pulmonologist (lung specialist), to make sure that it is not cancerous, especially if you are a former smoker or have a nonsmoking first relative with lung cancer.
Hearing the word “cancer” can be stressful. Don’t panic—but do talk to your doctor about your concerns and what your next step should be. A diagnosis of lung cancer can bring up a wide range of feelings that you’re not used to dealing with and it is natural to feel overwhelmed.
Balancing the need to discuss your feelings, gather information, and initiate treatment as early as possible can be understandably frustrating. In addition, you may be asked to quit smoking, change your eating habits, and limit alcohol—all of which are difficult things to do.
The key is to take things one day at a time. In many cases early treatment is curative, so it is encouraged that you ask questions, learn about your diagnosis, and do not delay medical intervention for any reason.
Frequently Asked Questions
Is a lung nodule a neoplasm?
The terms “lung nodule” and “neoplasm” are often used interchangeably as they both refer to a small abnormal area, or mass, that may be benign or malignant and is sometimes found during imaging of the chest.
What percentage of lung neoplasms are benign?
Although the exact percentage of benign lung neoplasms varies based on which study you look to, the vast majority of lung neoplasms are benign.
What is malignant neoplasm of the bronchus and lung?
Malignant neoplasms are an abnormal number of damaged cells that preferentially grow in the bronchus, alveoli, or other parts of the lung. The uncontrollable growth and invasion of these cells into other tissues is called cancer.