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Solitary Pulmonary Nodule (cont.)

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.
Medically Reviewed by a Doctor on 2/9/2016

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Solitary Pulmonary Nodule - Cause

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