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Symptoms and Signs of Solitary Pulmonary Nodule

Doctor's Notes on Solitary Pulmonary Nodule

A solitary pulmonary nodule (SPN) is a single abnormal spot in the lung smaller than 3 cm in diameter that is surrounded by normal lung tissue and is not associated with any other abnormality in the lung or nearby lymph nodes. Solitary pulmonary nodules are usually noticed by chance on a chest X-ray film that has been taken for another reason (referred to as an incidental finding). Most solitary pulmonary nodules are benign (noncancerous) but they may represent an early stage of primary lung cancer or may indicate that cancer is spreading (metastasizing) from another part of the body to the lung.

Most people who have solitary pulmonary nodule do not experience symptoms and the solitary pulmonary nodules are detected as an incidental finding. About 20% to 30% of all lung cancer cases first appear as solitary pulmonary nodules on chest X-ray films. Solitary pulmonary nodules should be considered potentially cancerous until proven otherwise.

Medical Author: John P. Cunha, DO, FACOEP
Medically Reviewed on 3/11/2019

Solitary Pulmonary Nodule Symptoms

Most persons with solitary pulmonary nodule do not experience symptoms. Generally, solitary pulmonary nodule is detected as an incidental finding.

Approximately 20% to 30% of all cases of lung cancer appear as solitary pulmonary nodules on chest X-ray films. Therefore, the goal of investigating an solitary pulmonary nodule is to differentiate a benign growth from a malignant growth as soon and as accurately as possible.

Solitary pulmonary nodules should be considered potentially cancerous until proven otherwise.

People should always communicate openly and honestly with their health care professional about their history and risk factors.

The following features are important when assessing whether the solitary pulmonary nodule is benign or malignant.

  • Age: Risk of malignancy increases with age.
    • Risk of 3% at age 35 to 39 years
    • Risk of 15% at age 40 to 49 years
    • Risk of 43% at age 50 to 59 years
    • Risk of greater than 50% in persons older than 60 years
  • Smoking history: A history of smoking increases the chances of the solitary pulmonary nodule being malignant.
  • Prior history of cancer: People with a history of cancer in other areas of the body have a greater chance that the solitary pulmonary nodule is malignant.
  • Occupational risk factors for lung cancer: Exposure to asbestos, radon, nickel, chromium, vinyl chloride, and polycyclic hydrocarbons increases the chance that the solitary pulmonary nodule is malignant.
  • Travel history: People who have traveled to areas with endemic mycosis (for example, histoplasmosis, coccidioidomycosis, blastomycosis) or a high prevalence of tuberculosis have a higher chance of the solitary pulmonary nodule being benign.
  • People who have a history of tuberculosis or pulmonary mycosis have a greater chance of the solitary pulmonary nodule being benign.

Solitary Pulmonary Nodule Causes

Solitary pulmonary nodules may have the following causes:

  • Neoplastic (an abnormal growth that can be benign or malignant)
    • Lung cancer
    • Metastasis (spread of cancer from other parts of the body to the lung)
    • Lymphoma (a tumor made up of lymphoid tissue)
    • Carcinoid (a small, slow-growing tumor that can spread)
    • Hamartoma (an abnormal mass of normal tissues that often contain many different cell types such as hair or teeth)
    • Fibroma (a tumor made up of fibrous connective tissue)
    • Neurofibroma (a noncancerous tumor made up of nerve fibers)
    • Blastoma (a tumor composed mainly of immature, undifferentiated cells)
  • Sarcoma (a tumor made up of connective tissue [usually cancerous])
  • Inflammatory (infectious): Granuloma (small, granular inflammatory lesions) These usually involve an exposure to an infectious agent. This agent is difficult for the body to completely remove so the immune system attacks trying to wall it off. Because the immune cells are coming from all angles, the resultant biproduct is a rounded nodular density, an solitary pulmonary nodule.
  • Infection caused by bacteria: for example, tuberculosis
  • Infections caused by fungi: Histoplasmosis, coccidioidomycosis, blastomycosis, cryptococcosis, nocardiosis
  • Other infectious causes
    • Lung abscess (an infection in which cells of a part of the lung die)
    • Round pneumonia (infection caused by virus or bacteria, air spaces of the lungs are filled with fluid and cells)
    • Hydatid cyst (a cyst formed by the larval stage of a tapeworm, Echinococcus or other parasitic agents such as paragonamus westermani);
  • Inflammatory (noninfectious)
    • Rheumatoid arthritis (a generalized disease of the connective tissues, joint pain is the main symptom, the rheumatoid nodules can show up when the arthritis may be very mild or asymptomatic)
    • Wegener granulomatosis (inflammation of the small blood vessels known as vasculitis, often affecting the kidneys and sinuses as well as the lungs)
    • Sarcoidosis (a disease characterized by granular lesions of unknown cause that involves various organs of the body, and now believed to be in some way related to noninfectious inflammation against proteins from bacteria in the tuberculosis family)
    • Lipoid (resembling fat) pneumonia
  • Congenital
    • Arteriovenous malformation (failure of proper or normal development of arteries and veins)
    • Sequestration (a piece of lung tissue that has become separated from the surrounding healthy tissue often an embryonic developmental abnormality)
    • Lung cyst (an abnormal sac that contains gas, fluid, or a semisolid material, with a membranous lining, a malformation that occurs during embryologic development)
  • Miscellaneous
    • Pulmonary infarct (death of cells or of a portion of lung, resulting from a sudden insufficiency of arterial or venous blood supply to a small portion of the lung)
    • Round atelectasis (decreased or absent air in a part of the lung)
    • Progressive massive fibrosis (formation of fibrous tissue as a reactive process, as opposed to formation of fibrous tissue as a normal constituent of an organ or tissue)
    • Occasionally, a shadow seen on X-ray from an overlying object lying on the back or the chest may be mistaken for an solitary pulmonary nodule. Similarly, when several objects, such as blood vessels, lymph nodes, and or ribs overlap, the result can seem like a nodule or mass on chest X-ray when one does not really exist.

COPD Lung Symptoms, Diagnosis, Treatment Slideshow

COPD Lung Symptoms, Diagnosis, Treatment Slideshow

COPD is the abbreviation for chronic obstructive pulmonary disease. COPD is a lung disease that results from obstructions in the airways of the lungs that lead to breathing problems. Although COPD is a progressive disease, early diagnosis and treatment may slow its progression. COPD may be complicated by chronic bronchitis or emphysema; some patients develop both problems that lead to additional breathing problems. Some clinicians consider chronic bronchitis and emphysema as simply further manifestations of COPD.

How Does COPD Affect the Lungs?

Damage to the lung tissue over time causes physical changes in the lungs and the airways become clogged with thick mucus. Compliance (the ability of the lung tissue to expand) becomes weakened because of this lung tissue damage. This weakened compliance or elasticity of the lungs means that oxygen cannot get to the air spaces where oxygen and carbon dioxide exchange occurs in the lung. This all leads to coughing to remove the thick mucus and eventually, difficulty in breathing.


Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.