Hamartoma (chondro-adenoma) is a rare benign lesion that can occur in different tissues like cartilage, bone and fibrous cells. Hamartomas tend to occur in children and young adults but are very rare in elderly people. The hamartoma can occur in almost any organ and is usually asymptomatic. The lesion has a firm marble-like consistency. It is important to note that the lesion is not malignant and radical surgery is almost never required.
When a hamartoma is suspected in an individual, determining whether a mass is benign or malignant based solely on its anatomical location is a major error in judgment. Anatomical location has no predictability on the malignant potential of a certain lesions. Most hamartomas are found as an asymptomatic nodule on a routine plain x-ray, which then leads to further work up. During the patient’s history, one should ask about any smoking history, exposure to chemicals, previous malignant tumor, recent travel and type of work.
The majority of hamartomas are discovered incidentally when working up a patient for another disorder. Sometimes the patient may report a mass and in other cases, the mass may be seen on an x-ray or CT scan. However, depending on where the hamartoma is located, some symptoms may arise and include the following:
The diagnostic approach is basically the same for all masses. Clinical presentation depends upon the location of the tumor.
There is no specific blood work requires for hamartomas. however, if the patient is symptomatic or about to undergo surgical excision, an ECG, urine analysis and blood coagulation parameters must be ordered. An arterial blood gas may be obtained to determine the presence of any lung disorder. All patients about to undergo a lung resection are best served with pulmonary function tests to determine their suitability for surgery. Other blood work depends on location of the hamartoma. If a liver lesion is suspected, the liver function tests should be ordered. All patients are asked to stop smoking for at least 3-4 weeks prior to surgery and pulmonary rehabilitation is undertaken.
The first imaging test of choice is always the plan x-ray. However, the plain x-ray is not sensitive for hamartomas and may not even identify small lesions. The plain x-ray may help identify bone fractures or areas of bone thinning. On the plain x-ray, hamartomas usually appear as well circumscribed tumors with smooth margins. Even though calcification is seen in about 15% of lesions, it may not always be visible on x-ray. The radiographic pattern of calcification may resemble popcorn, and although virtually diagnostic, this appearance is not common. Benign lesions tend to have calcium deposited in central, concentric, peripheral, homogeneous or “popcorn” patterns, whereas an irregular pattern of calcification is more likely to be a feature of malignancies. Serial x-rays may show either fast or slow growth, making differentiation from carcinoma difficult. Cavitation is rare seen with hamartomas. In the absence of characteristic popcorn pattern of calcification, x-ray evidence of calcification or evidence of focal areas of fat, the differential diagnosis must include all other solitary nodules, especially cancer.
Bone scans may be used to differentiate a benign from a malignant lesion. If the patient has evidence of vascular involvement, then angiography is useful.
Since the plain x-ray is not sensitive, the CT scan with and without contrast is recommended as it can help define the calcification. In addition, the CT scan can also help make a diagnosis of AV malformation and can reveal the presence of a malignancy. CT scan with use of iodinated contrast dye also provides more details about the size, presence of satellite lesions, status of lymph nodes, and, when used in conjunction with noncontrast studies, more detailed definition of calcification. Specific popcorn like calcifications are almost pathognomonic for a pulmonary hamartoma. The major difficulty with hamartomas is distinguishing them from inflammatory and metastatic lesions.
MRI has a limited role in evaluation of hamartomas. Focal areas of calcium and fat can be missed because of lack of signal. MRI is useful in defining tumor invasion of the great vessels and chest wall. MRI is superior to CT scan in defining the mediastinum, chest wall invasion and aortopulmonary window adenopathy. MRI is not always available, is expensive and does not really decipher a benign lung tumor from a malignant nodule. MRI though is useful when looking at lesions in the spinal cord and is much more sensitive than CT scan when assessing soft tissue masses.
If a hamartoma is suspected in the airways, Fiberoptic bronchoscopy is very important to evaluate all central lung masses. If the tumor is located centrally, bronchial washing and/or biopsy can be performed. If the mass is a polyploid lesion with a stalk, then the entire mass can be excised at the stalk. Bronchoscopy lacks sensitivity for detecting malignancy for peripheral masses.
Needle biopsy has become a standard approach to making a diagnosis of hamartoma  .The technique can be combined with either fluoroscopy or CT scan to improve its accuracy. The location of the mass is the most important determining factor for a needle biopsy. Needle biopsy tends to yield more positive results than simple aspiration. The procedure is usually done in a radiology suite. Complications of needle biopsy include bleeding, pain, pneumothorax, infection and failure to make a diagnosis.
Contraindications to biopsy
A needle biopsy or any surgical approach for biopsy of a mass should not be done in the presence of a bleeding diathesis and cardiopulmonary conditions, which may place the patient's life at risk.
Hamartomas are composed of normal components of the lung tissues. On histologic sections they are composed mainly of hyaline cartilage and glandular tissue that may include fat. The myxoid connective tissue is surrounded by smooth muscle and clefts lined by epithelial cells. However, the mature cells are unorganized and haphazardly arranged. In the lung, histologic studies might show how that the peripheral epithelial line the clefts. Foci of undifferentiated mesenchymal or fibroblast-like cells are frequently present at the periphery of the cartilaginous tissue. Cartilage is always present and is a characteristic feature of hamartomas.
When a peripheral hamartoma is examined, it is usually a firm mass consisting of lobules of cartilaginous tissue. It is surrounded by a zone of loose fibroblastic tissue. Fatty tissue, smooth muscle cells and monocytes may also be seen in varying proportions. Calcification and ossification is not always present, but when present it can be extensive. This feature accounts for the typical “popcorn calcification” seen on x-rays. In the lung and bone hamartomas are morphologically indistinguishable from malignant lesions but appear more fleshy, polyploid and are often densely adhered to the underlying tissues.
There is no medical therapy for hamartomas apart from observation. The majority of hamartomas are found on an incidental exam. Since most hamartomas cause no symptoms, the treatment is usually conservative. If the hamartoma is compression a nerve or causing pain, analgesics may be administered. If the symptoms persist, then excision may be required.
General indications for surgery include the following:
The majority of patients do not require any type of intervention. For those who do require a surgical procedure, this may include a biopsy to rule out a cancer. Other procedures used to remove hamartomas include curettage or fixation of a fracture. In rare cases, a digital amputation may be required.
In patients with a solitary nodule suspected of being a hamartoma in a young nonsmoking patient, one may elect to monitor the individual with serial radiographs as long as the solitary nodule does not double in size in less than a year. The mass should not significantly increase its pattern of calcification and shape consistent with a malignancy, nor should it cause symptoms. Unless an absolute clinical diagnosis of hamartoma can be made, conservative resection is the treatment of choice.
Today hamartomas can be excised using the open technique of using video assisted techniques, depending on where the lesion is located. The lesions can be enucleated without difficulty. It is important to remember that hamartomas are benign lesions and radical surgery is almost never required. Unless the mass is compressing or invading delicate structures, all efforts must be made to remove only the lesion and avoid damage to the normal adjacent tissues.
If one elects to follow the hamartoma clinically, it is recommended that a plain x-ray be obtained regularly. Protocols vary as to the exact timing of x-rays, but one should be obtained every 3-6 months for the first year, then every 12 months in the following year. Some experts recommend that a yearly CT scan should be complementary study if there are any signs of change on the x-ray. This protocol is only recommended in reliable patients who can be followed up. For those who might be lost to follow up or live too far from the medical center, a small surgical procedure will eliminate both the need for follow up and patient/physician anxiety.
Generally, hamartomas do not grow and remain stable in size. However, some hamartomas can grow over time and often tend not to have characteristic calcification. Small hamartomas may not be present in previous x-rays and thus, may not present with symptoms. In such cases, both the patient and the surgeon may be anxious enough to seek a surgical consult. Although hamartomas are benign and do not pose a significant health problem, complications can result if the lesion is compressing a nerve, blood vessel or airway. Overall, these tumors are considered benign, and, therefore, their malignant/cancerous potential is minimal. When there is any doubt, the safest course is to remove it surgically and confirm the diagnosis.
The diagnosis of a hamartoma in almost any part of the body in no way limits normal life expectancy, nor does it predispose the patient to any type of malignancy. The hallmark of surgical treatment of such benign lesions is conservative resection, whenever possible.
Overall, no recurrent tumors have been seen in many series over a period of 20 years. However, there are a few reports of additional hamartomas occurring after resection. The recurrences have frequently been seen after a period of 3-6 years. Other rare reports indicate that perhaps there is an increased risk for subsequent development of pulmonary carcinoma in patients who have hamartomas. Today, these reports are anecdotal. For the present, it is perhaps safer, more cost-effective and less stressful to have the lesion excised and the histology confirmed.
The exact cause of hamartomas is unknown. In some cases, hamartomas have been associated with polyposis and other central neural disorders. Hamartomas have been described in the following organs or medical disorders:
The exact incidence of hamartomas is not known because in most cases these lesions are asymptomatic and never come to medical attention. The majority of hamartomas are only discovered on an incidental exam when the patient is being worked up for another medical disorder. Sometimes the lesions are seen on x-ray and at other times they are discovered during an autopsy. The majority of series on hamartomas indicate that these lesions are most common in children and young adults. Overall, hamartomas are slightly more common in men than women. Most lesions are first identified in the 3rd-4th decade of life. Hamartomas account for nearly 70% of benign coin lesions of the lung.
Hamartomas can occur in almost any organ but are most prevalent on cartilage, bone and fibrous tissues. Although the majority of lesions are less than 2-4 cm in size, some may be as large as 8-10 cm. Hamartomas have been reported in all races.
Hamartomas are thought to be derived from embryonic remnants, representing an abnormal collection of normal tissue components of the organ in which they are found. The tumor consists of disorganized collection of smooth muscle cells, cartilage and collagen. These tumors are believed to arise in the connective tissues, bone or cartilage. They tend to be well circumscribed, lobulated and the contiguous tissues may be condensed. Sometimes the tumor may be calcified and appear like a “popcorn” lesion.
Rarely there maybe multiple hamartomas which may occur in either the same organ or at a different anatomical site. Reports of recurrences after excision have also been reported. Hamartomas chiefly occur in bone, cartilage, and soft or fibrous tissues.
The cause of hamartoma is not known and hence prevention strategies do not exist. Patients who have a systemic disorder like neurofibromatosis, cowden disease or peutz jegher syndrome need follow up with their healthcare provider to ensure that the lesions are not causing any symptoms.
The term hamartoma was first coined by Albrecht, who in 1904 described a disorganized arrangement of normal tissues present in an organ. A hamartoma is a mass composed of tissues that are normally present in the organ in which the tumor occurs, but the tissue elements are disorganized. Histologically, hamartomas consists of cleft epithelial tissue and other tissues such as fat and cartilage. When a hamartoma is believed to exist in the tissues, the most important diagnostic consideration is to rule out a malignancy. Except for a biopsy, there is no absolute method of confirming the presence of a hamartoma. Hamartomas can be easily enucleated during surgery. Unless the lesion has invaded local tissues, major resection is rarely required [1-3].
Hamartoma is a benign lesion that may occur in any part of the body including bone, soft tissue and cartilage. In most cases, these lesions do not cause any symptoms and are discovered as an incidental finding. In rare cases, a hamartoma will cause pain, swelling, bleeding or a cough. The diagnosis of a hamartoma is made with a needle biopsy. The decision to treat a hamartoma depends on patient preference. These lesions are harmless and can be observed. They do not become cancerous. However, if you feel anxious or are worried, then surgery to remove the lesion is usually curative.