What are lung nodules?
A lung nodule is a growth that appears at the level of the lungs. The size and the form of the lung nodule varies from one patient to the other. The lung nodules can appear in one or both lungs, leading to a wide range of symptoms. One can also present just one or multiple lung nodules. There are certain risk factors that contribute to the appearance of the lung nodules, such as: age, smoking habit and pre-existing conditions.
How common are nodules on lung?
The lung nodules have become increasingly common in the past few years, being often encountered in patients diagnosed with different types of cancer. As you will have the opportunity to read in the diagnosis section, the lung nodules are most often identified through CT scanning performed at the level of the chest. It is said that over half of the smokers who are over 50 years of age present such lung nodules.
Can lung nodules be cancerous?
Even though the majority of the lung nodules are benign (non-cancerous), there are patients who present malign (cancerous) growths at the level of their lungs. As it was mentioned above, the cancerous lung nodules are often diagnosed in patients who are long-term smokers and present a more advanced age. In many situations, the doctor might recommend the constant monitoring of the benign nodules, so as to make sure that they do not transform into cancerous growths.
Types of lung nodules
According to the appearance of the CT scan, the lung nodules can be classified into the following types:
- Solid nodule – complete obscuring of the surrounding parenchyma (well-defined margins)
- Semisolid nodule – partial obscuring of the surrounding parenchyma
- Ground-glass nodule – this is also known as a non-solid nodule (difficult to interpret and diagnose, due to the area of haziness and the margins that are not clearly defined)
The majority of the patients who present nodules on the lungs are asymptomatic (the symptoms become obvious in the more advanced stages of the disease). However, these are the most common symptoms associated with the nodule on lung:
- Coughing (the patient has difficulties stopping from the couch)
- Coughing up blood
- Difficulty breathing or shortness of breath
- In case of chronic infection, such as pneumonia, the patient might also present systemic symptoms (such as fever)
These are the major causes that can lead to the appearance of nodules on the lungs:
- Fungal infection – most common: aspergillosis, coccidioidomycosis, cryptococcosis and aspergillosis
- Abscess at the level of the lung
- Pneumonia – chronic infection, common in adults
- Rheumatoid arthritis
- Wegener granulomatosis
- Birth defects – cysts or malformations at the level of the lungs
- Hamartomas – these are benign tumors of the lung, leading to the formation of solitary nodules. The nodules resemble marbles, being located at the lung periphery
- Bronchial adenoma – this is also a benign tumor that occurs at the level of the lungs, arising from the mucous glands
- Rare types of cancer – chondroma, neurofibroma or lipoma (these are tumors that originate from the connective or the fatty tissue)
The diagnosis of the lung nodules is made with the following measures:
Chest X-ray and CT scans
- These methods of investigation allow for the identification of the pulmonary nodules
- The nodules are often identified through these methods of investigation accidentally (the patient goes to the doctor for a routine check-up or because of a respiratory illness)
- Based on the results of the investigation, the doctor will be able to analyze the size, shape and location of the lung nodule (the diameter is also important). In general, a nodule that is large in size and irregular in shape, presents an increased risk for being a cancerous growth
- Medical history (cancer in the past)
- Identification of risk factors – smoking, exposure to chemicals or toxic substances (occupational hazard, no protective equipment in harmful environment)
- Comparison of old X-rays/CT scans with new ones – see the growth of an existent nodule (risk of cancer)
Positron emission tomography (PET)
- Useful in making the difference between a malignant and benign
- Using a special substance that is absorbed by the nodule, the doctor can see the activity of the cells at that level
- It is important to understand that the malignant nodules are more active, thus absorbing the substance more easily
- The PET imaging will reveal the lighting of the nodules, especially if they are malignant or there is a lot of associated inflammation
- The nodules that are smaller in size are not seen that well on the PET imaging
- The doctor takes a small sample from the lung nodule – this sample is analyzed in the lab, so as to determine whether it is malignant or not
- There are two main procedures through which the biopsy can be performed:
- Bronchoscopy – the doctor inserts a small tube through the mouth or the nose, traveling all the way to the lungs and reaching the nodule. Using specific tools and guided by the camera, the doctor will collect the necessary sample for the biopsy
- Needle biopsy – this procedure is also known as transthoracic needle aspiration. The doctor makes a small incision through the chest wall and reaches the nodule (guided by CT scans). This is recommended for the nodules that are located close to the edge of the lungs.
Benign nodules do not require treatment, especially if they do not cause any symptoms or bring discomfort to the patient.
For the malign nodules or the ones producing symptoms, these are the most common methods of treatment recommended for lung nodules:
Surgical intervention – removal of the lung nodule through:
- Thoracotomy – open surgery, in which the chest wall is cut and the lung nodule is removed (requires several days of hospitalization). Depending on the severity of the condition, a mini-thoracotomy can be performed (advantage – less invasive)
- Video-assisted thoracoscopy – using a special tube that has a camera attached to it, the doctor will enter the chest wall through a small incision and remove the nodule. The surgeon visualizes the area of intervention with the camera attached to the tube. This is considered a minimally-invasive procedure, providing a more efficient and faster recovery.