Overview of the disease
A single nodule or spherical lesion up to 3 cm in diameter in the lungs, usually asymptomatic and related to genetic, environmental and disease factors, which can be followed and observed, or treated individually to address the cause of the disease.
Definition
A single round or spherical lesion up to 3 cm in diameter in the lungs, completely encapsulated by lung tissue, without hilar and/or mediastinal lymph node enlargement, pleural effusion, or atelectasis.
Classification
Isolated pulmonary nodules can be categorized into micronodules, small nodules and pulmonary nodules according to the size of the diameter of the nodule; and solid nodules, sub-solid nodules and ground glass nodules according to the density of the nodule.
Classification according to nodule diameter
Micronodule
Isolated pulmonary nodules with a diameter of less than 5 mm.
Small nodule
Isolated pulmonary nodules with a diameter of less than 10 mm.
Pulmonary nodule
Isolated pulmonary nodules with a diameter of 30 mm or less.
Classification according to nodule density
Solid nodules
Nodules in the lungs have an elevated soft tissue density, the density of the nodule is relatively uniform, and the blood vessels and bronchial shadows that travel within the nodule are obscured.
Sub-solid nodules
Nodules in the lungs are not uniform in density, contain both solid soft tissue density and ground glass density, and have the highest degree of malignancy.
Frosted glass nodules
Intrapulmonary nodules are slightly denser than the surrounding lung parenchyma, but blood vessels and bronchial shadows are visible within the nodule.
Depending on the severity of the nodule
Benign nodules
Account for the majority of isolated pulmonary nodules, including malignant tumors, infected granulomas, and lipomas.
Malignant nodules
Include malignant lesions such as lung cancer, carcinoid tumors, and lung metastases.
Causes
Causes
Isolated pulmonary nodules are seen in a variety of diseases.
Neoplasm
Malignant tumor
These include mainly peripheral bronchopulmonary carcinoma, isolated nodular lung metastases, lung lymphoma, bronchial carcinoid tumors, and other rare lung malignancies (e.g., pulmonary sarcoma).
Benign tumors
Mainly include misshapen tumors, hemangiomas, smooth muscle tumors, etc.
Infectious
Mainly including tuberculosis ball, spherical pneumonia, pneumonic pseudotumor, aspergillus ball, lung abscess, histoplasmosis, parasitic disease, etc.
Pulmonary vascular anomalies
Mainly include pulmonary arteriovenous malformation, hemangioma due to Behcet’s disease, pulmonary embolism, pulmonary hemorrhage, etc.
Abnormal growth and development
Such as lung fluid-containing bronchial cysts, pulmonary isolation, etc.
Immunologic diseases
Mainly include vasculitis, rheumatoid pulmonary nodules, etc.
Others
Such as pulmonary lymphoproliferative disorders (nodular lymph node hyperplasia, lymphomatoid granuloma, giant lymph node hyperplasia, etc.), primary bronchopulmonary amyloidosis abnormal projections of the chest wall, etc.
Symptoms
Main symptoms
Symptoms vary depending on the cause of the disease and may even be absent.
If there is a primary disease, the patient may show related symptoms, such as fever, chills, cough, sputum and other symptoms due to lung infection.
Complications
Complications vary according to the cause of the disease and the involvement of surrounding tissues.
Hemoptysis
Hemoptysis may occur when an isolated pulmonary nodule encroaches on the surrounding blood vessels or pulls on the neighboring bronchial tubes.
Atelectasis, Obstructive Pneumonia
Large isolated pulmonary nodules may compress or obstruct the surrounding bronchial tubes, causing atelectasis, or obstructive pneumonia if the obstruction is so severe that airway secretions cannot be expelled.
Consultation
Department of Medicine
Respiratory Medicine
If pulmonary nodules are found on physical examination or respiratory symptoms such as coughing, coughing up sputum, hemoptysis, chest tightness, etc., it is recommended to consult a doctor promptly.
Thoracic Surgery
Thoracic Surgery can also be consulted if lung nodules are found during physical examination.
Preparation
Consultation: registration, preparation of information, common problems
Tips for Consultation: Registration, Preparation of Documents, Frequently Asked Questions
Physical cooling, such as warm water baths, can be used to reduce fever before consultation, but self-medication is not recommended.
If there are obvious clinical symptoms, record the time of onset and change of symptoms for reference.
Checklist for medical preparation
Symptom list
Time of onset of symptoms, special manifestations, etc.
Are there any symptoms such as fever, cough, sputum, hemoptysis, chest pain, dyspnea, weight loss, etc.?
How long have these symptoms been present?
How often do these symptoms come on? How long does each attack last? What can be done to relieve them?
Medical History Checklist
Have you had regular physical examinations in the past? Are there any pulmonary nodules found on physical examination?
Is there a history of long-term heavy smoking (≥30 pack-years of smoking, including those with ≥30 pack-years of previous smoking and less than 15 years of current smoking cessation), passive smoking, or dust exposure?
Any history of lung infection, connective tissue disease, pulmonary vascular lesions, malignant tumors, etc.?
Is there any relevant medical history in immediate family members such as parents, siblings, children, etc.?
Checklist
Examination results in the last six months, which can be brought to the doctor’s office
Imaging tests: chest radiograph, chest CT, etc.
Laboratory tests: tumor markers, blood routine, etc.
Medication list
Medication in the last 3 months, if available, bring along the box or package for medical consultation
Antibiotics: e.g. Amoxicillin, Levofloxacin, Cefaclor, etc.
Antifungal drugs: e.g. fluconazole, voriconazole, etc.
Anti-tuberculosis drugs: e.g. isoniazid, rifampicin, etc.
Diagnosis
Diagnosis is based on
Medical history
Isolated pulmonary nodules are imaging manifestations and the diagnosis is not dependent on history.
However, history of smoking, dust exposure, and previous diseases (e.g., lung infections, connective tissue disease, pulmonary vascular lesions, malignant tumors, etc.) may provide a reference for identifying the etiology.
Clinical manifestations
There may be no obvious clinical symptoms, some patients may have cough, sputum, hemoptysis, chest pain, dyspnea and other symptoms.
Imaging
Chest X-ray
Large isolated pulmonary nodules can be found, which is of some significance to the diagnosis of the disease.
Most isolated pulmonary nodules less than 1cm in diameter cannot be visualized on chest radiographs, so chest radiographs are not used for routine evaluation of isolated pulmonary nodules.
Chest CT
Chest CT is the preferred test and is important for the diagnosis of isolated pulmonary nodules.
Chest CT can show the location, size, morphology, density and margins of lung nodules clearly from multiple angles and in an all-round way.
In particular, thin-layer high-resolution CT can better show the characteristics of lung nodules, and is often used as the first choice of examination for small lung nodules.
Functional imaging (PET-CT)
It can show the function and metabolism of isolated lung nodules, and is important for identifying the benign or malignant nature of nodules with a diameter greater than 8 mm.
The uptake of malignant nodules is higher, and the likelihood of malignant nodules increases significantly when the standardized uptake value of isolated pulmonary nodules is greater than 2.5.
However, PET-CT has no significant advantage in identifying the benign and malignant nature of nodules less than 8 mm in diameter.
Magnetic resonance imaging (MRI)
Magnetic resonance imaging (MRI) is superior to CT in the visualization of chest soft tissues and mediastinal vessels, and is important in identifying the benign or malignant nature of nodules.
The sensitivity of MRI for malignant nodules can be up to 100% with dynamic enhancement and perfusion.
MRI is more sensitive and accurate than CT in identifying metastatic and non-metastatic lymph nodes.
Laboratory Tests
Tumor markers
Can provide a reference for etiologic diagnosis and differentiation of isolated pulmonary nodules.
Commonly examined items include gastrin-releasing peptide precursor (Pro-GRP), neurospecific enolase (NSE), carcinoembryonic antigen (CEA), cytokeratin fragment 19 (CYFRA21-1), and squamous cell carcinoma antigen (SCC).
If a patient has elevated levels of these tumor markers, especially if they are progressive, be alert to the possibility of malignant nodules.
Blood count, C-reactive protein, calcitoninogen
The patient can be evaluated for co-infections.
If the infection is due to or induced by obstructive pneumonia, the blood counts may indicate elevated leukocytes and elevated C-reactive protein.
Calcitonin may be elevated in bacterial infections.
Tuberculosis-related tests
It is important to identify whether it is caused by tuberculosis infection.
Commonly used tests include blood sedimentation, PPD, tuberculosis spot test/γ-interferon release test, TB-DNA, sputum for antacid bacilli.
Biopsy
It is mainly used to clarify the etiology of isolated pulmonary nodules.
Fiberoptic bronchoscopy
It is a routine method to examine and diagnose the cause of isolated pulmonary nodules, and the sensitivity to malignant pulmonary nodules is 20%～80%.
It can be performed by direct bronchoscopic brushing, biopsy, lavage fluid to obtain a cytohistologic diagnosis or transbronchoscopic lung biopsy.
Percutaneous lung aspiration biopsy
It has high diagnostic sensitivity and specificity for peripheral isolated pulmonary nodules.
It can be performed under CT or ultrasound guidance.
Surgical biopsy
For patients who are unable to obtain pathologic specimens by means of bronchoscopy and percutaneous lung aspiration biopsy.
It mainly includes thoracoscopy and mediastinoscopy.
Differential Diagnosis
Isolated pulmonary nodules are an imaging manifestation that is primarily aimed at differentiating the etiology of the nodule, although there are still some cases where the etiology cannot be clarified.
Treatment
Treatment aims:
Benign nodules: regular follow-up and timely intervention to avoid malignant changes when there is a tendency for malignancy.
Malignant nodules: early intervention to improve prognosis and prolong survival.
Treatment principles:
At present, there is no clear and unified treatment strategy for isolated pulmonary nodules.
It is recommended to adopt individualized treatment measures based on comprehensive analysis of clinical features, imaging manifestations, and malignant tendency.
General treatment
Changing bad lifestyle habits
Smokers should quit smoking and avoid exposure to second-hand smoke.
Air pollution such as haze and dust should be avoided as much as possible.
Observation and follow-up
If the nodule is judged to be benign by the specialist, regular observation and follow-up can be conducted.
For isolated lung nodules that cannot be determined to be benign or malignant for the time being, the next step of treatment should be decided by the specialist based on the probability of malignancy and risk factors.
Etiologic treatment
For patients with benign isolated lung nodules that have a clear cause, etiologic treatment is required.
Medication
If infection is considered to be the cause, anti-bacterial, anti-fungal, and anti-tuberculosis drugs can be used.
Anti-bacterial drugs
For patients with isolated pulmonary nodules due to bacterial infection.
Commonly available drugs include amoxicillin, cephalosporins (e.g., cefaclor, ceftriaxone, cefotaxime, etc.), levofloxacin, moxifloxacin, and so on.
Antifungal drugs
For patients with isolated pulmonary nodules due to fungal infection.
Commonly used are fluconazole, voriconazole, itraconazole and so on.
Anti-tuberculosis drugs
Suitable for patients with isolated pulmonary nodules due to tuberculosis infection.
Isoniazid, rifampicin, pyrazinamide, ethambutol, etc.
Surgery
Television thoracoscopic surgery (VATS) is usually chosen, and open thoracic surgery can also be chosen for malignant nodules that are difficult to be resected by television thoracoscopic surgery.
Indications
Isolated pulmonary nodules that require surgical resection after evaluation.
Isolated pulmonary nodules that are considered malignant during follow-up.
Malignant isolated pulmonary nodules, but with small diameter and without metastasis.
Contraindications
Pleural hypertrophy and adhesions so severe that thoracoscopy is inaccessible.
Coagulation disorders.
Malignant nodules have developed extensive metastasis.
The pleura and blood vessels have been invaded, and resection is difficult.
Severe respiratory and circulatory dysfunction, poor general condition and other conditions that cannot tolerate surgery and anesthesia.
Prognosis
The majority of isolated pulmonary nodules are benign, and the overall prognosis is favorable, with most of them not affecting the patient’s natural life expectancy.
Even for malignant isolated nodules, as long as they are diagnosed in time and receive standardized treatment as early as possible, the prognosis is still good and the five-year survival rate is high.
Only some patients with malignant nodules that are detected late and not treated in time can develop advanced tumors that are incurable and have a relatively poor prognosis.
Daily
Daily Management
Dietary management
No special dietary contraindications.
It is recommended to develop good dietary habits, maintain balanced nutrition, and consume more fresh fruits and vegetables to enhance immunity.
Daily Care
Quit smoking while avoiding exposure to air pollution.
Strengthen physical exercise to enhance immunity.
Relax your mind and keep optimistic.
Disease monitoring
Patients should pay attention to whether they have worsening cough and sputum, and symptoms of infection such as fever and chills.
Note whether there is dyspnea and other signs of airway obstruction.
In addition, it is also necessary to pay attention to the presence of lethargy, poor appetite and other symptoms of malignant disease.
If any of the above situations occurs, it is necessary to consult a doctor in time.
Follow-up examination
Strictly follow the review schedule set by the specialist, and regularly review the chest CT, tumor markers, etc. If malignant transformation of the nodules is detected during the follow-up, it should be treated promptly.
Prevention
Staying away from tobacco, avoiding air pollution, strengthening occupational protection, actively treating lung inflammation, and regular medical checkups are effective measures to prevent isolated pulmonary nodules.
Stay away from tobacco
Smokers should strictly quit smoking and non-smokers should avoid passive smoking.
Avoid air pollution
Wear a good protective mask in hazy weather and use an air purifier if necessary.
Avoid excessive exposure to oil smoke and soot in daily life.
Strengthen occupational protection
Occupational groups engaged in mining, metallurgy, decoration, painting and other occupations with long-term exposure to dust and chemicals should strengthen occupational protection, strictly observe occupational protection norms, and wear protective gear that meets the standards.
Active treatment of lung inflammation
When bacterial, fungal, tuberculosis and other infectious diseases of the lungs are found, active and standardized treatment is required.
Regular medical checkups
Regular medical checkups are of great significance for early detection, diagnosis and treatment of the disease and other diseases. People with high risk factors for lung cancer should undergo low-dose chest CT screening on a regular basis.