Multiple pulmonary nodules - Causes and Symptoms

Definition

Multiple pulmonary nodules are lesions most frequently found in cases of malignant neoplasms, infections or underlying rheumatological diseases.

Primitive lung tumors usually come in the form of a solitary nodule; among the various subtypes, bronchiolo-alveolar carcinoma is most frequently associated with the appearance of multiple nodularities. Although many malignant neoplasms can metastasize to the lungs, certain histotypes have a greater propensity to present with multiple nodules. These include malignant neoplasms of colon, breast, prostate, thyroid, kidneys and testicles, melanomas and sarcomas. Non-Hodgkin's lymphoma and Wegener's granulomatosis can also occur with multiple pulmonary nodules.

Peripheral nodules, especially those with cavitation, indicate the presence of a septic embolus. In these cases, the suspicion of infections increases, therefore it is appropriate to perform a blood culture.

Multiple calcific nodules suggest a previous granulomatous disease, including a previous histoplasmosis or a mycobacterial infection, such as tuberculosis. Immunocompromised patients may present secondary nodules to many other infectious agents.

Several rheumatological diseases may present with multiple pulmonary nodules; among these, rheumatoid arthritis is the most common etiology.

Other causes are exposure to silicon (silicosis), talc (talcosis) or coal dust (pneumoconiosis). Sputum analysis, bronchoalveolar lavage bronchoscopy, serological examinations, and more rarely a surgical lung biopsy are all investigations that play a role in making the diagnosis.