What is the clinical significance of calcified lymph nodes in the subcarinal and right infrahilar regions?

From the Guidelines

Calcified lymph nodes in the subcarinal and right infrahilar regions are typically benign and represent healed granulomatous disease, but may cause symptoms if they erode into adjacent airways, as seen in broncholithiasis, and therefore, require further evaluation if symptoms are present. The clinical significance of these calcified lymph nodes lies in their potential to cause respiratory symptoms such as cough, hemoptysis, and recurrent pneumonia if they impinge on or erode into the airway lumen 1. These calcifications most commonly result from prior infections such as tuberculosis, histoplasmosis, or other fungal infections that have resolved, leaving behind calcium deposits as a form of scarring.

Key Considerations

• The presence of calcified lymph nodes alone, without other concerning radiographic findings or symptoms, generally does not require intervention beyond routine follow-up.
• However, if these findings are new or if symptoms like persistent cough, weight loss, or fever are present, further evaluation is recommended to rule out active infection or malignancy 1.
• A comparison with previous imaging studies can help determine if these are longstanding or new findings.
• Additional tests such as sputum cultures, tuberculosis testing, or bronchoscopy may be recommended if there are concerns about active disease.

Diagnostic and Therapeutic Approach

• Bronchoscopy is the most definitive diagnostic test to identify broncholithiasis and is also useful in the treatment of broncholithiasis, with the potential to remove broncholiths and alleviate symptoms 1.
• Removal of the stones bronchoscopically or surgically is recommended if they are causing symptoms or complications 1.

From the Research

Clinical Significance of Calcified Lymph Nodes

The clinical significance of calcified lymph nodes in the subcarinal and right infrahilar regions can be understood through various studies that have investigated the pattern and distribution of calcified mediastinal lymph nodes in different diseases.

• Calcification of lymph nodes is a common finding in granulomatous diseases such as sarcoidosis and tuberculosis 2.
• A study found that the mean short axis diameter of calcified nodes was significantly larger in sarcoidosis patients than in TB patients, and the pattern of calcification also differed between the two diseases 2.
• In the context of lung cancer, calcified lymph nodes are generally considered a benign feature, but a study found that the frequency of metastasis to calcified lymph nodes was around 20% 3.
• The size of calcification is an important factor, with major calcification (>5 mm) having a lower frequency of metastasis than minor calcification 3.

Distribution and Pattern of Calcification

The distribution and pattern of calcification in lymph nodes are important factors in determining the underlying disease.

• A study found that the subcarinal region was the most common location for lymphadenopathy in children suspected of primary pulmonary tuberculosis, followed by the hila 4.
• The pattern of calcification can also vary, with focal, diffuse, eggshell, and complete nodal replacement by calcification being reported in different studies 2, 5.
• The presence of calcified lymph nodes in the subcarinal and right infrahilar regions can be an indicator of tuberculosis or other granulomatous diseases, but it is not a reliable predictor of benign or malignant disease 5.

Diagnostic Implications

The presence of calcified lymph nodes in the subcarinal and right infrahilar regions has important diagnostic implications.

• Calcified lymph nodes can be detected on computed tomography (CT) scans, and the size and pattern of calcification can provide important clues about the underlying disease 2, 3.
• A study found that the frequency of metastasis to calcified lymph nodes was higher in patients with minor calcification (<5 mm) than in those with major calcification (>5 mm) 3.
• The presence of calcified lymph nodes in the subcarinal and right infrahilar regions should be considered in the context of other clinical and radiological findings to determine the underlying disease 4, 6.