Pulmonology

Pulmonary nodule

Most pulmonary nodules are benign, especially in people under 35 years of age.

What is a pulmonary nodule?

Pulmonary nodules are small masses of tissue in the lung, usually less than 3 centimeters in diameter, that are found on a chest X-ray or computed tomography (CT) scan. They are surrounded by healthy lung parenchyma and are not associated with atelectasis (lung collapse), enlarged lymph nodes at the hilum (the area where blood vessels and bronchi enter and exit the lung), or pleural effusion (fluid accumulation around the lung). They can be benign (noncancerous) or malignant (cancerous). If the lesion is larger than 3 cm, it is considered a lung mass, which has a higher probability of being malignant.

Análisis de radiografía para valorar salud pulmonar

Symptoms of pulmonary nodules

In the vast majority of cases, pulmonary nodules do not cause any noticeable symptoms. They are usually discovered incidentally during a chest X-ray or computed tomography (CT) scan of the chest performed for other health reasons. However, when the nodules are large or malignant (cancerous), some symptoms may appear, although they are often nonspecific and can be mistaken for other respiratory conditions. The most common symptoms include:

Cough:

a persistent cough or one that worsens over time may be a sign of a pulmonary nodule. It can be a dry cough or a productive cough (with mucus). In some cases, especially if the nodule is irritating an airway, there may be coughing up blood (hemoptysis), although this is more common in cancerous nodules.

Chest pain:

chest pain associated with a pulmonary nodule can be dull or sharp, constant or intermittent. It may worsen when breathing deeply or coughing. The location of the pain does not always correspond to the location of the nodule.

Shortness of breath (dyspnea):

if a nodule is large or is blocking a main airway, it can make breathing difficult. Shortness of breath can be mild or severe, and may worsen with physical exertion.

Wheezing:

wheezing is a whistling sound when breathing, which may indicate that the airways are inflamed or narrowed by a nodule.

Recurrent respiratory infections: 

in some cases, a pulmonary nodule can increase susceptibility to infections such as pneumonia or bronchitis.

It is important to note that these symptoms are not exclusive to pulmonary nodules and may be present in other respiratory diseases. If you experience any of these symptoms, especially if you smoke or have other risk factors for lung cancer, it is essential to consult a doctor for an appropriate evaluation.

Classification of pulmonary nodules

Pulmonary nodules are primarily classified according to their appearance on radiological images, especially based on their density:

Solid nodules: they appear as opaque, homogeneous white spots on CT scans. They are the most common type of pulmonary nodule.

Subsolid nodules (ground-glass): they have a more translucent and blurry appearance on CT scans, similar to a fogged-up window. They are divided into two subtypes:

Pure ground-glass nodules, which are completely translucent.

Partially solid nodules, which contain a solid component and a ground-glass component.

The classification of pulmonary nodules helps doctors assess the risk of malignancy. Subsolid nodules, especially partially solid ones, are often associated with a higher risk of lung cancer than solid nodules. Other characteristics, such as size, shape, and the presence of calcifications, are also considered in the evaluation of the nodule.

Causes of pulmonary nodules

A pulmonary nodule can originate from a wide variety of causes, which often makes it difficult to characterize. Infections are a common cause, and can be bacterial, such as pneumonia or a lung abscess; fungal, such as histoplasmosis or coccidioidomycosis; or even parasitic.

Inflammatory diseases can also manifest as pulmonary nodules, with sarcoidosis and granulomatosis being common examples. Neoplasms, both benign and malignant, represent another possible cause. Benign nodules can be hamartomas or adenomas, while malignant nodules can correspond to primary lung cancer or metastases from other cancers.

In addition, there are other less frequent causes, such as arteriovenous malformations, cysts, scars from previous infections, and pulmonary embolisms. Given the diversity of possible causes, it is essential to perform a complete medical evaluation to determine the origin of the pulmonary nodule.

Risk factors for pulmonary nodules

While most pulmonary nodules are benign, some factors increase the likelihood that a pulmonary nodule is malignant:

Age: the risk of lung cancer increases significantly with age. Pulmonary nodules in people over 60 years of age have a higher probability of being cancerous.

Smoking: smoking is the main risk factor for lung cancer. The risk is greater the longer and the more cigarettes have been smoked. Even after quitting smoking, the risk remains elevated for many years.

Family history of lung cancer: having a close relative (father, brother, or son) with lung cancer increases individual risk.

Exposure to environmental carcinogens: exposure to substances such as asbestos, radon, arsenic, chromium, nickel, and some industrial chemicals increases the risk of lung cancer.

Personal history of cancer: having had cancer previously, even if it was not lung cancer, increases the risk of developing a new cancer, including lung cancer.

Pre-existing lung diseases: certain lung diseases, such as chronic obstructive pulmonary disease (COPD) and pulmonary fibrosis, may increase the risk of developing lung nodules and lung cancer.

Diagnosis of a pulmonary nodule

La The diagnostic approach to the finding of a pulmonary nodule is based on a systematic approach that combines different methods to determine its nature (benign or malignant) and its underlying cause. The diagnostic process generally includes the following steps:

Detailed medical history: the doctor will review the patient’s medical history, including smoking history, exposure to environmental carcinogens, family history of lung cancer, and any symptoms present. The physical examination may include listening to the lungs to detect abnormal sounds.

Imaging tests: they are essential for characterizing the pulmonary nodule and for follow-up. For small, low-risk nodules with benign characteristics, surveillance can often be chosen, which involves performing periodic computed tomography (CT) scans to monitor the nodule and detect any changes in its size or appearance. If the nodule is suspected of being malignant or if it has grown over time, further studies such as a positron emission tomography (PET) scan may be required to assess its metabolic activity.

Biopsy: if imaging tests suggest that a nodule may be malignant, a biopsy can be performed to obtain a tissue sample and analyze it under a microscope. There are several biopsy methods. During bronchoscopy, a thin, flexible tube (bronchoscope) is inserted through the nose or mouth into the lungs. Tissue samples can be obtained from the nodule through the bronchoscope. In CT-guided needle biopsy, a thin needle is inserted through the skin into the nodule, guided by CT images. A tissue sample is extracted through the needle. In some cases, surgery may be necessary to obtain a tissue sample from the nodule. This can be done through a small incision (thoracoscopy) or a larger incision (thoracotomy).

The differential diagnosis of a pulmonary nodule is crucial to distinguish between the various possible causes, including infections, inflammation, benign neoplasms, and cancer. The doctor will consider all findings from the medical history, physical examination, and imaging tests to arrive at an accurate diagnosis and determine the most appropriate treatment.

Management of pulmonary nodules

The management plan for a pulmonary nodule should be individualized based on the degree of suspicion, which will depend on several factors (size, location, and characteristics of the nodule), as well as the patient’s risk factors and overall health status. Management options include:

Surveillance: for small, benign-appearing nodules, periodic monitoring with computed tomography (CT) scans is recommended to monitor their growth or any changes. The frequency of CT scans will depend on the size and characteristics of the nodule.

Treatment of the underlying cause: if the pulmonary nodule is caused by an infection, it will be treated with antibiotics or antifungals. If it is caused by inflammation, corticosteroids or other immunosuppressive drugs may be used.

Surgery: if the nodule is suspected of being malignant or if it has grown over time, surgery to remove it may be recommended. The type of surgery will depend on the size and location of the nodule, as well as the patient’s overall health. Types of surgery include wedge resection, where only a small portion of the lung containing the nodule is removed, segmentectomy, where a segment of the lung is removed, or lobectomy, which involves removing an entire lobe of the lung.

The treatment of a pulmonary nodule should be individualized and planned by a multidisciplinary team of specialists, including pulmonologists, radiologists, thoracic surgeons, and oncologists, to ensure the best possible outcome for each patient.

Remember that this article is for informational purposes only and does not replace professional medical advice. If you suspect you have a pulmonary nodule, consult a specialist to obtain an accurate diagnosis and an appropriate treatment plan tailored to your needs.