What is Pulmonary Hamartoma?
Pulmonary hamartomas are noncancerous growths in the lungs, made up of an unusual combination of tissue types such as cartilage (the firm, flexible tissue found in the body), connective tissue, fat, and epithelium (the skin’s outer layer). They are the most common benign (noncancerous) lung tumors in adults. In contrast, they’re quite uncommon in children. These tumors, first identified by German pathologist Eugen Albrecht in 1904, can appear in various body parts, including the lungs, skin, heart, and breast, amongst others. The term ‘hamartoma’ originates from the Greek word ‘hamartia’, meaning mistake or fault. This is because the cells of a hamartoma have a jumbled mixture of tissue types that you would normally expect to see in the organ where it grows, but the organ’s usual structure is usually not preserved within the tumor.
These lung tumors grow slowly, typically show no symptoms, and are often discovered by accident. From a chest x-ray or scan, they look like clear, round or lobed structures, usually less than 3 cm across, often found in the outer parts of the lung. This means you don’t usually see signs of pressure or damage to surrounding structures from the growth of these tumors.
When it comes to treating pulmonary hamartomas, two methods involving surgical removal are usually preferred: enucleation, which is the removal of the tumor while leaving the surrounding tissue in place and wedge resection, where a small, wedge-shaped piece of lung containing the tumor is removed. However, for bigger tumors, or if there are multiple tumors or tumors in tricky locations, it might be necessary to perform more invasive surgeries, including removal of a lung lobe, a procedure modifying the airways, or removal of a lung. For patients at risk of their tumor turning cancerous, or those with existing primary lung cancer, surgeries involving the removal of a larger portion of the lung are recommended. Hamartomas that have grown into the airways can often be effectively removed using an instrument to look into the airways (a bronchoscope).
What Causes Pulmonary Hamartoma?
In the past, there haven’t been any specific risk factors linked to the development of pulmonary hamartomas. Pulmonary hamartoma are benign, tumor-like growths composed of disarranged tissue elements typically found within the affected organ. It’s worth noting that sometimes these growths can transform and show particular changes in the genetic code. No specific guidelines are in place yet for early detection of a pulmonary hamartoma.
A hamartoma is the most common noncancerous growth in the lungs. They make up between 1.4% and 20% of all growths within the chest area and are the most commonly found noncancerous growths in the bronchi – the major airways leading from the trachea (windpipe) to the lungs.
While most people with hamartomas that form within the lung tissue have no symptoms, those with an isolated bronchial hamartoma may experience symptoms. These can include pneumonia, coughing up blood, a cough, or difficulty breathing.
Risk Factors and Frequency for Pulmonary Hamartoma
Pulmonary hamartomas are usually found in adults, particularly in those aged around 50-60 years old. Men are four times more likely to encounter these than women. Despite still being fairly uncommon, they are the most frequently found benign lung growth, forming approximately 77% of non-cancerous lung nodules and 8% of single lung lesions. Most of these growths are located in the outer lung tissue, but some can also be found in the central chest wall. About 10% of these growths are located inside the bronchi (air tubes in the lungs). Among children, pulmonary hamartomas are extremely rare.
When considering factors such as age, sex, and ethnicity, people with pulmonary hamartomas have a risk of developing lung cancer which is 6.3 times higher than in the regular population.
or “comma-shaped” appearance of calcification is pathognomonic for hamartomas.
Signs and Symptoms of Pulmonary Hamartoma
Parenchymal hamartomas, typically, do not cause any symptoms in adults and are often discovered by accident. However, depending on the size and location of these growths, some people might experience symptoms such as:
- Persistent coughing or wheezing
- Shortness of breath (dyspnea)
- Coughing up blood (hemoptysis)
- Rumbling sound in the chest (rhonchi)
- Increased chance of catching pneumonia
- Airway obstruction
- Collapse of part or all of a lung (atelectasis) or even collapsed lung (pneumothorax)
If hamartomas begin causing symptoms, it’s important that a thorough diagnostic approach is taken to identify the cause, and in some cases, surgical removal of these growths may become necessary.
Testing for Pulmonary Hamartoma
Hamartomas, a kind of benign (noncancerous) lung tumor, might be discovered accidentally while doctors are looking at lung images for another reason. They might look similar to lung cancer on these images, causing some concern. When a hamartoma is found, or if a hamartoma isn’t causing any symptoms, there are several ways to figure out what the lung lesion is.
On images like chest X-rays or CT scans, these lung lesions often look like coin-shaped, single masses with clear edges. They’re usually smaller than 4 cm (about 1.5 inches) across. In about 25% to 30% of cases, there may be calcification, which means there is too much calcium in the lung tissue. If this calcification looks like popcorn or a comma, it’s a sure sign that the lung lesion is a hamartoma.
Although CT scans are the best way to image hamartomas, sometimes further tests are needed. A special kind of scan that uses a substance called fluorodeoxyglucose can help determine how fast the lesion is growing and how much it’s affecting the body’s metabolism. This is helpful for lesions that have an unclear risk of cancer.
In some special cases, for example if the lesions don’t have any fat in them or don’t show the usual pattern of calcification, a biopsy is needed to make sure there is no hidden cancer. This usually involves using a bronchoscope (a type of camera that can look inside the lungs) and a fine needle to get a small sample of the lesion.
If a lung lesion has the typical appearance of a hamartoma and meets certain criteria on a CT scan, such as being smaller than 4 cm, having clear edges, having detectable calcification, or having a fatty component, it can be monitored regularly without any immediate need for treatment. Surgery to remove the lesion is only recommended for lesions that are growing quickly, are causing symptoms, or might be cancerous.
Treatment Options for Pulmonary Hamartoma
Surgery is the only sure-fire cure available for lung lesions. The main goal of such surgery is to keep as much healthy lung tissue as possible. Therefore, the most common types of surgery are enucleation, where the lesion is removed without removing much healthy tissue, and wedge resections, where a small, triangle-shaped piece of lung is removed. More intense procedures like removing an entire lung lobe (lobectomy) or the whole lung (pneumonectomy) are saved for more severe cases. This might include situations with multiple or large lesions, or lesions tightly adhered to a vital part of the lung. Doctors generally recommend doing a quick test of the tissue while the operation is ongoing to check for signs of cancer.
Most cases of a benign lung tumor known as a pulmonary hamartoma are less than 2.5 cm and don’t necessarily need removal if they exhibit characteristics of a hamartoma or don’t grow overtime. However, if the lesion is quite large, it may need to be removed because it could cause breathing problems or carry a risk of cancer. For example, a resection was initially believed to be necessary in a documented case due to suspicion that it was a different type of tumor entirely, based on how it looked in radiographs. Other documentation has shown cases of large hamartomas measuring 8 to 20 cm, where patients were experiencing significant symptoms like breathlessness and heavy bleeding from the lungs. In such cases, it’s important for healthcare professionals to discuss evaluation and potential resection at a joint conference.
What else can Pulmonary Hamartoma be?
When looking at a possible hamartomatous lesion (a growth that can look like a cancerous tumor but is not), the most important thing is to make sure it isn’t actually cancer. After ruling out cancer, other non-cancerous lung tumors should be considered if a single lung nodule is detected. These can include infectious granuloma, lipoma, lipoid pneumonia, or pulmonary papilloma.
It’s also worth noting that while most of these are standalone occurrences, these types of lesions can sometimes occur alongside genetic syndromes. For example, multiple lung hamartomas can be a sign of either the Carney triad or Cowden syndrome. The Carney triad is often found in young women and is indicated by the simultaneous presence of a certain type of stomach tumour, lung hamartomas, and types of tumours found outside the adrenal glands. Cowden disease, on the other hand, usually results in multiple hamartomas, skin lesions, multiple non-cancerous tumours in internal organs, and increased risk for several types of cancer, including breast and digestive tract cancers.
It is also important to differentiate between various types of benign solid tumours that show ossification or calcification, like hamartomas, pulmonary amyloidomas, and pulmonary osteomas. Here’s what you need to remember about them:
- Hamartomas: They often present as solitary lung nodules and sometimes as endobronchial tumors. They’re made up of hyaline cartilage, fibromyxoid stroma (connective tissue), smooth muscle cells, and fat tissues. On CT scans, they often show fat or calcification.
- Pulmonary Amyloidosis (Amyloidoma): This is due to localized buildup of amyloid proteins in lung tissues. On CT scans, it shows up as a solitary lung nodule, multiple nodules, or in more widespread patterns. The exact diagnosis is confirmed by special microscopic examination techniques.
- Pulmonary Osteoma: This refers to bone lesions composed of lamellar bone with special channels (Haversian canals). They appear as dense lesions on CT scans that resemble normal bone cortex, and mature types may also show bone marrow. Although some may suspect such a case to be an instance of pulmonary hamartoma with ossification, this is a point of caution and further analysis.
What to expect with Pulmonary Hamartoma
The outlook for patients with lung hamartoma, a noncancerous lung tumor, is typically very good. These tumors grow slowly, and if they cause symptoms that don’t go away, surgery can be a cure. Lung hamartomas turning cancerous or causing a separate instance of cancer is uncommon.
Patients following a regular check-up routine are likely to have any dangerous tumors diagnosed early. Early diagnosis can lead to effective treatments and increase the chances of successful recovery.
Possible Complications When Diagnosed with Pulmonary Hamartoma
Pulmonary hamartomas, or noncancerous lung tumors, can sometimes cause complications. One potential issue is blockage of airways, which can lead to collapse of lung sections (atelectasis) or repeated instances of pneumonia. In rare cases, these hamartomas may turn into cancerous tumors, a process called sarcomatous transformation. When these lung tumors start to grow rapidly or cause overall body symptoms like weight loss, weakness, or fatigue, it could be a sign of this cancerous change. However, this might not always be clear when looking at the cells under a microscope. Other signs, like the tumor spreading into nearby tissues or other parts of the body, may be more noticeable.
There have been observations that link certain genetic abnormalities to the occurrence of pulmonary hamartomas. These abnormalities often involve changes to the genes 12q14 and 6q21, that produce a protein called high mobility group A. Also, research shows that people with pulmonary hamartomas are six times more likely to get lung cancer compared to individuals without these noncancerous tumors. This suggests that there may be a genetic tendency for these people to either have their hamartomas turn cancerous or develop cancer separately.
Important Facts:
- Pulmonary hamartomas can block airways leading to collapsed lung or repeated pneumonia.
- Rapid growth or systemic symptoms like weight loss, weakness or fatigue could indicate these have turned cancerous.
- A link between certain genetic changes and pulmonary hamartomas has been observed.
- People with pulmonary hamartomas are six times more likely to develop lung cancer.
Preventing Pulmonary Hamartoma
Pulmonary hamartomas, which are unusual growths in the lungs, seem to appear without any known risk factors. Basically, there is no definitive way to predict or prevent them because they typically occur randomly and unexpectedly. Also, there are no specific guidelines on how to monitor for this condition. However, even though the chance of these growths turning into cancer is very low, it’s still recommended that patients follow a regular check-up routine. This involves repeated imaging studies (like X-ray or CT scans) over time and comparing them to previous ones. Doing this allows doctors to keep an eye on the condition and notice any changes that might suggest a problem.
