A calcified pulmonary nodule occurs when a person's immune system isolates objects that it considers foreign, forming a granuloma, or clump of cells, notes Cleveland Clinic. Granulomas can calcify over time as the tissue heals and calcium collects in it.
Granulomas form when lung tissue is inflamed due to infections such as tuberculosis, aspergillosis or histoplasmosis, reports Cleveland Clinic. Granulomas can also be caused by other infections, including coccidiomycosis and cryptococcosis. Pulmonary nodules can be caused by noninfectious conditions such as Wegener's granulomatosis, rheumatoid arthritis and sarcoidosis.
Neoplasms can lead to pulmonary nodules, notes Cleveland Clinic. Neoplasms can be benign or malignant. Benign neoplasms may be hamartomas, neurofibromas, blastomas or fibromas. Malignant neoplasms may be caused by lung cancer, or these neoplasms may be sarcomas, carcinoids, lymphomas or metastatic tumors.
Typically pulmonary nodules do not manifest with any symptoms, explains Cleveland Clinic. The underlying cause of the lung nodule may cause symptoms. Typically pulmonary nodules are detected with chest X-rays or CT scans.
Pulmonary nodules are usually benign and are found on up to half of all lung CT scans, states Cleveland Clinic. Smoking and older age are risk factors for malignant pulmonary nodules. When a patient has benign nodules, treatment is not typically necessary. If the nodule is malignant or if a biopsy is not conclusive, a physician typically recommends surgically removing the nodule. Pulmonary nodules are usually removed via a thoracotomy or a video-assisted thoracoscopy.