What are the causes of pulmonary granuloma?

From the Guidelines

Pulmonary granulomas are most commonly caused by sarcoidosis, tuberculosis, fungal infections, and hypersensitivity pneumonitis, as supported by the most recent and highest quality study 1. The causes of pulmonary granuloma can be diverse, but the most common ones include:

• Sarcoidosis: a chronic, multisystem, granulomatous disease of unknown cause, most commonly seen in young and middle-aged adults 1
• Tuberculosis: a bacterial infection that can cause granulomas in the lungs
• Fungal infections: such as histoplasmosis, which can cause granulomas in the lungs
• Hypersensitivity pneumonitis: a lung disease caused by an allergic reaction to inhaled substances, which can lead to granuloma formation 1 Other less common causes of pulmonary granulomas include:
• Wegener granulomatosis: a systemic vasculitis that can cause necrotizing granulomatous vasculitis of the upper and lower respiratory tract 1
• Berylliosis: a lung disease caused by exposure to beryllium, which can lead to granuloma formation 1
• Aspiration: bronchiolocentric inflammation frequently with foreign material and giant cell or histiocytic reaction 1 It's essential to note that the diagnosis of pulmonary granuloma requires a combination of clinical, radiographic, and histopathological findings, and the treatment depends on the underlying cause. The most recent and highest quality study 1 provides the most up-to-date information on the diagnosis and evaluation of hypersensitivity pneumonitis, which is one of the common causes of pulmonary granuloma.

From the Research

Causes of Pulmonary Granuloma

The causes of pulmonary granuloma can be categorized into infectious and non-infectious forms.

• Infectious causes include:
  • Mycobacterial infections, such as tuberculosis 2, 3, 4, 5
  • Fungal infections 3, 6, 5
  • Parasitic infections 3
  • Bacterial infections, such as mycobacteriosis 2
• Non-infectious causes include:
  • Sarcoidosis 2, 3, 6, 4, 5
  • Hypersensitivity pneumonitis 2, 3, 6, 4, 5
  • Vasculitis 6
  • Hot tub lung 3, 4, 5
  • Aspiration pneumonia 2, 4, 5
  • Talc granulomatosis 5
  • Berylliosis 3
  • Necrotizing sarcoid granulomatosis 3
  • Bronchocentric granulomatosis 3
  • Drug-induced granulomas 3
  • Chronic granulomatous disease 3
  • Common variable immunodeficiency 3
  • Granulomatous lesions associated with various types of cancer 3

Distribution of Granulomas

The distribution of granulomas in the lung can also aid in diagnosis.

• Granulomas can be distributed along lymphatic vessels, as seen in sarcoidosis 2, 4
• Random distribution of granulomas can be seen in miliary infections, such as mycobacterial and fungal infections 2, 4
• Distribution along the airways can be seen in hypersensitivity pneumonitis, hot tub lung, and aspiration pneumonia 2, 4

Diagnosis

Diagnosis of pulmonary granuloma requires a multidisciplinary approach, including clinical, radiological, and pathological assessment 2, 3, 4.

• A combined radiological-histopathological approach can aid in defining the morphological features and anatomic localization of granulomatous lung diseases 2, 4
• Special stains and cultures can help identify the underlying cause of the granuloma 3, 5
• Correlation with clinical, radiologic, and laboratory data is essential for narrowing down the differential diagnosis 6