From the Guidelines
The tree-in-bud pattern seen in lung nodules at the lung base is significant as it indicates inflammation or infection in the small airways, and prompt medical evaluation is necessary to guide appropriate treatment. This pattern appears when the terminal bronchioles become filled with mucus, pus, or fluid, creating a branching pattern that resembles a budding tree on imaging studies 1. The most common causes are infectious bronchiolitis (particularly from tuberculosis, nontuberculous mycobacteria, or bacterial pneumonia), aspiration, and sometimes inflammatory conditions like bronchiectasis. When found at the lung base specifically, it often suggests aspiration-related infection or conditions where secretions pool in dependent areas of the lungs.
According to the most recent guidelines, the management of incidentally detected indeterminate pulmonary nodules should be based on the nodule's size, attenuation, morphology, and the patient's risk factors for lung cancer 1. For nodules larger than 6 mm, follow-up CT scans, PET/CT, or tissue sampling may be recommended, depending on the nodule's characteristics and the patient's clinical probability of cancer.
The tree-in-bud pattern is important to recognize because it helps differentiate infectious processes from other lung pathologies like malignancy or interstitial lung disease, guiding appropriate treatment. Additional testing such as sputum cultures or bronchoscopy may be needed to identify the specific cause of the tree-in-bud pattern. Treatment duration usually ranges from 7-14 days for bacterial infections, though may be longer for mycobacterial infections.
It is essential to note that the management of lung nodules should be individualized, taking into account the patient's risk factors, comorbidities, and preferences. The American College of Radiology (ACR) Appropriateness Criteria and the American College of Chest Physicians (ACCP) guidelines provide recommendations for the management of incidentally detected indeterminate pulmonary nodules, emphasizing the importance of a multidisciplinary approach and patient-centered care 1.
In summary, the tree-in-bud pattern in lung nodules at the lung base is a significant finding that requires prompt medical evaluation and appropriate treatment to prevent morbidity and mortality. The most recent guidelines should be consulted to guide the management of incidentally detected indeterminate pulmonary nodules, and a multidisciplinary approach should be taken to ensure optimal patient care.
From the Research
Significance of Tree-in-Bud Pattern in Lung Nodule at Lung Base
The tree-in-bud pattern is a radiologic finding that can be seen on high-resolution computed tomography (CT) scans of the lungs. It is characterized by small centrilobular nodules of soft-tissue attenuation connected to multiple branching linear structures of similar caliber that originate from a single stalk.
Causes of Tree-in-Bud Pattern
The tree-in-bud pattern can be caused by a variety of conditions, including:
- Infectious diseases such as tuberculosis, bacterial, fungal, viral, or parasitic infections 2, 3, 4
- Congenital disorders, idiopathic disorders, and immunologic disorders 2, 5
- Aspiration or inhalation of foreign substances 2, 3, 5
- Malignant conditions, such as lung cancer 6, 5
- Peripheral pulmonary vascular diseases, such as neoplastic pulmonary emboli 2
Clinical Significance
The tree-in-bud pattern can be an important diagnostic finding, as it can indicate the presence of an underlying condition that requires treatment. For example, in patients with lung cancer, the tree-in-bud pattern can be a sign of obstructive bronchial mucoid impaction distal to the cancer 6. In patients with infectious diseases, the tree-in-bud pattern can indicate the presence of an infection that requires antibiotic treatment 3, 4.
Radiologic Findings
The tree-in-bud pattern can be associated with other radiologic findings, such as: