From the Guidelines
Calcified hilar lymph nodes are generally not clinically significant in most cases, but they can be pertinent in certain clinical scenarios where they impinge on or erode into the airway lumen, causing respiratory symptoms. These calcifications typically represent the body's healing response to previous infections or inflammatory processes, most commonly from prior granulomatous diseases like tuberculosis, histoplasmosis, or sarcoidosis [ 1 ]. Once calcified, these lymph nodes usually indicate an inactive or resolved process rather than ongoing disease. However, as noted in the study on broncholithiasis, calcified hilar and mediastinal lymph nodes can cause clinical and roentgenographic abnormalities when they encroach on adjacent airways [ 1 ].
Some key points to consider when evaluating calcified hilar lymph nodes include:
- The presence of respiratory symptoms such as cough, hemoptysis, or recurrent pneumonia [ 1 ]
- The location and size of the calcified lymph nodes, as well as any changes on serial imaging [ 1 ]
- The patient's clinical presentation, risk factors, and other imaging findings [ 1 ]
- The possibility of broncholithiasis, which can be diagnosed and treated with bronchoscopy [ 1 ]
In general, if a patient has no symptoms and the calcifications appear stable on serial imaging, they typically require no specific treatment or intervention. However, incidental calcified hilar lymph nodes found on chest imaging generally warrant documentation and may require further workup if accompanied by concerning clinical features or radiographic changes [ 1 ].
From the Research
Clinical Significance of Calcified Hilar Lymph Nodes
- Calcified hilar lymph nodes can be a common response to chronic inflammation and are rarely associated with any clinical findings 2
- However, normal respiratory movements can cause erosion into adjacent bronchi, leading to a broncholith, which can result in morbidity 2
- Calcified lymph nodes can also cause clinically relevant attenuation correction artifacts on PET/CT imaging, which can lead to misinterpretation and potential patient mismanagement 3
Management and Complications
- Calcified hilar lymph nodes can hamper the conventional process of pulmonary artery dissection during thoracoscopic lobectomies, and require special techniques to avoid vessel injuries and conversions 4
- A new technique, the "scissor first" technique, has been developed to manage calcified hilar lymph nodes during thoracoscopic lobectomies, which provides an effective solution for avoiding arterial injury and conversion 4
- Calcified lymph nodes can also be a manifestation of Pneumocystis carinii infection in AIDS patients, and can cause significant diagnostic confusion 5
Prognostic Implications
- Calcified lymph nodes on computed tomography (CT) in patients with lung cancer are generally considered to be a benign feature, but can still have a frequency of metastasis of about 20% on both a per-person and a per-nodal station basis 6
- The size of calcification can be a risk factor associated with metastases, with major calcification (>5 mm) having a significantly lower frequency of metastasis than minor calcification (≦5 mm) 6