Introduction
Lung aspergilloma is the formation of a fungal ball that is composed of Aspergillus hyphae, cellular debris, and mucus. It is formed in the pre-existing cavities in the lung parenchyma, which are created by previous conditions. This formation can also occur in the brain, kidney, or other organs. It can also be seen in paranasal sinuses.
What Is Lung Aspergilloma?
An aspergilloma is a fungal ball or clump of mold that is composed of aspergillus hyphae, cellular debris, and mucus. Lung aspergilloma is the formation of a fungal ball in the cavities of the lung. It can exist anywhere in the body cavities like paranasal sinuses, sphenoid sinuses, ear canals, and heart valves or organs like the lungs, brain, kidneys, or other organs. Aspergillosis is a fungal infection caused by breathing aspergillus spores from the environment.
What Are the Causes of Lung Aspergilloma?
Lung aspergilloma is caused by the aspergillus species - Aspergillus fumigatus. It usually affects the lungs. It affects individuals with underlying conditions that cause lung cavities like tuberculosis, sarcoidosis, bronchiectasis, cystic fibrosis, pneumoconiosis, post-infarct pulmonary cavity, post-radiation pulmonary cavity, bronchial cysts and bullae, chronic lung abscess, lung malignancy, and ankylosing spondylitis. It is also seen in individuals affected with COVID-19 infection (coronavirus disease).
It can occur in individuals with conditions impairing bronchopulmonary defense, like malnutrition, chronic obstructive pulmonary disease (COPD), and chronic liver diseases. It affects individuals with immunosuppressive conditions like post-transplant, stem cell transplant, chemotherapy, neutropenia, prolonged steroid use, HIV (human immunodeficiency virus) infection, and primary immunodeficiency syndromes.
How Does Lung Aspergilloma Occur?
The aspergillus spores enter through the respiratory tract. They also colonize the external ear canal. This species proliferates in a diseased lung or with immunodeficiency. They harbor the cavitary spaces, adhere to the wall with their conidia, germinate, and induce an inflammatory response in the process. It then forms an amorphous mass or a fungal ball known as aspergilloma. It initially presents as an ulceration or cobblestoned cavity wall or floor.
A cavity is a well-defined space that harbors the fungal spores and isolates the spores from mechanical clearance and immune eradication. Lung aspergilloma is divided into simple and complex types. In simple aspergilloma, the surrounding lung parenchyma is normal, and the cavity containing the nidus is lined by ciliated epithelium. The complex aspergilloma is lined by extensively damaged lung parenchyma with epithelial distortion and fibrosis, with a wall thickness of more than 0.3 centimeters.
Aspergilloma is mobile within the cavitary spaces and keeps changing its position. Aggressive aspergilloma can expose and erode into a wider-branched pulmonary arterial system. Inflammation, hypoxia, and structural distortion can stimulate the opening up of pulmonary arterial and bronchial arterial anastomotic plexus. This becomes the target for erosion and hemoptysis. Multiple fungal ball formations are seen in conditions like chronic cystic bronchiectasis or multicystic or bullous disease.
In the brain, it invades the small, medium, and large vessels and causes hemorrhagic infarcts. These infarcts convert into septic infarcts, cerebritis, and abscesses.
What Are the Symptoms Associated With Lung Aspergilloma?
Aspergilloma does not cause any symptoms until it becomes an advanced condition. It results in bleeding if it invades the blood vessels. It causes hemoptysis (coughing up blood), which is the common symptom of aspergilloma. Fever, weight loss, chest pain, shortness of breath, fatigue, and malaise may occur. Recurrent pneumonia, chronic cough, or pulmonary fibrosis is seen if the aspergillus organism invades the surrounding parenchyma.
What Are the Complications Associated With Lung Aspergilloma?
Lung aspergilloma can result in the following complications:
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Massive hemorrhage due to hemoptysis.
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Formation of abscesses.
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Pulmonary fibrosis due to chronic inflammation.
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Breathing difficulties.
How Is Lung Aspergilloma Diagnosed?
The diagnosis of lung aspergilloma is based on CT (computed tomography) scan findings, sputum culture, and serum antibodies. Radiological findings, serological and microbiological evidence of aspergillus species, with symptoms lasting over three months, are the standard criterion for diagnosing lung aspergilloma.
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Chest X-Ray - Chest X-ray shows the presence of upper lobe cavitation, thickening, scarring, and round mass-like opacity within the cavity.
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CT Scan - CT scan shows the presence of a solid spherical lesion within the cavitary space. CT scan helps identify the cavity wall thickness, architectural distortion, inflammation of parenchyma and pleura, and relationship of the fungal ball with surrounding blood vessels. A halo sign with a surrounding inflammatory reaction around the cavity wall is seen. An air crescent sign that separates the fungal ball from the cavity wall or a part of its circumference is seen. A Monod sign is seen, which shows a change in the position of the fungal ball in the cavity, with a change in the position of the patient during radiographic imaging.
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Serum Antibodies - IgG (immunoglobulin G) antibodies against aspergillus species are detected. IgE antibodies are increased in this condition.
Immunoassay by double diffusion counter immunoelectrophoresis, immunofluorescence, and enzyme-linked immunosorbent assay tests are also useful in the diagnosis.
How Is Lung Aspergilloma Treated?
Surgical and nonsurgical treatment options are available, but it is decided based on the history of the disease and the risk of complications. Surgical treatment is decided based on the presence of hemoptysis. Antifungal therapy is given to patients with normal respiratory function.
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Wedge Resection is performed for small and simple aspergilloma.
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Pneumonectomy, Thoracotomy with Segmentectomy, or lobectomy is performed for multiple unilateral complex aspergillomas, megamycetoma, and intraoperative injury to the pulmonary artery.
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Systemic administration of Amphotericin and azoles is the main pharmacological management for aspergilloma. Intracavitary instillation of antifungal medication is also done.
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Bronchial artery embolization is done to treat hemoptysis. Recurrent hemoptysis is treated with radiotherapy and embolization.
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The radiofrequency ablation technique used in treating lung cancer is also a treatment option for lung aspergilloma.
Conclusion
Aspergilloma is a clump of mold found in pre-existing lung cavities. It usually remains asymptomatic. It presents with hemoptysis if the disease progresses. If patients are asymptomatic, it is usually diagnosed as an incidental finding. It is a treatable disease ad does not undergo spontaneous resolution. Since it affects immunocompromised individuals, a low-dose CT scan every six to twelve months is recommended for such patients. Early diagnosis and treatment can prevent fatal complications like hemoptysis.
