What are the round spots in the lung that appear to be growing and spreading, suggestive of pulmonary (lung) nodules or masses?

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Last updated: April 7, 2025 • View editorial policy

Differential Diagnosis for Round Spots in the Lung

Single Most Likely Diagnosis

  • Metastatic cancer: This is the most likely diagnosis, as round spots in the lung that are growing and spreading are often indicative of metastatic disease, particularly from primary tumors such as breast, lung, or colon cancer.

Other Likely Diagnoses

  • Pneumonia: Bacterial, viral, or fungal pneumonia can cause round spots in the lung, especially if the infection is multifocal.
  • Tuberculosis: Although classically described as having an upper lobe predominance, tuberculosis can present with round spots in the lung, particularly in immunocompromised patients.
  • Lymphoma: Both Hodgkin and non-Hodgkin lymphoma can cause pulmonary involvement, including round spots in the lung.

Do Not Miss Diagnoses

  • Pulmonary embolism: While not typically characterized by round spots, pulmonary embolism can cause infarcts that may appear as rounded lesions, and missing this diagnosis can be fatal.
  • Septic emboli: These can occur in the setting of endocarditis or other bacteremic conditions and can cause round spots in the lung due to septic infarcts.
  • Fungal infections: In immunocompromised patients, fungal infections such as aspergillosis or cryptococcosis can cause round spots in the lung and are critical to diagnose due to their high mortality rate if untreated.

Rare Diagnoses

  • Rheumatoid nodules: In patients with rheumatoid arthritis, pulmonary nodules can occur, although they are less common than other manifestations.
  • Wegener's granulomatosis: Now known as granulomatosis with polyangiitis, this condition can cause pulmonary nodules, including round spots, as part of its systemic vasculitis.
  • Pulmonary arteriovenous malformations: These can appear as round spots on imaging, particularly if they are multiple, and are important to diagnose due to the risk of paradoxical embolism.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.