Multiple Cartilaginous Exostoses

Multiple cartilaginous exostoses are multiple and hereditary exostoses. Benign bone tumors are based on an autosomal dominant mutation. Treatment consists largely of surgical removal of the tumor.

Multiple Cartilaginous Exostoses

What are multiple cartilaginous exostoses?

In the case of exostoses, there is a delimited new formation of compact bone substance that is directed outwards. Exostoses are hyperostoses, i.e. hyperplasia of the bone tissue, which are characterized by an increase in the number of cells. Most exostosis is a hyperplastic reaction. The bone changes in response to stimuli such as pressure. See foodezine for Everything about Keratitis-ichthyosis Deafness Syndrome.

In still other cases, exostosis is a benign tumor disease associated with the formation of osteomas and characterized by slow growth. There are also hereditary exostoses. An associated disease is multiple hereditary exostosis, MHE for short.

This is an autosomal dominant inherited disease characterized by multiple, benign bone tumors, also known as multiple cartilaginous exostoses. Although it is a congenital disease, the tumors are usually not present at birth.

The development usually begins in childhood or adolescence and corresponds to a slowly progressing development. The tumors are osteochondromas with hyaline cartilage. The incidence of the disease is given as one case in 50,000 people. With this frequency, the disease is one of the most common exostosis diseases, affecting women and men equally often.


Multiple hereditary exostoses is an inherited disease that has been observed to run in families. Around 70 percent of all patients have a familial form that is passed on in the autosomal dominant inheritance. In only about 30 percent of cases, the disease occurs sporadically. The causes of the phenomenon are to be found in genetics.

Hereditary mutations are present in the majority of all cases. In the sporadic proportion of those affected, the disease corresponds to a new mutation, which is probably related to exogenous factors such as environmental toxins. The causative mutations for multiple hereditary exostoses have now been identified. These are mutations in the EXT1 and EXT2 genes on chromosome 8 and chromosome 11.

These genes take over the coding for the proteins exostosin 1 and exostosin 2 in the DNA. The two proteins are so-called glycosyltransferases, which modify heparan sulfate within the Golgi apparatus. Heparan sulfate is a proteoglycan involved in angiogenesis.

Because of the mutations, the proteins that modify this substance are not properly assembled. How this mutation and the loss of function of enzymes is associated with the development of bone tumors remains unclear.

Symptoms, Ailments & Signs

The clinical picture of patients with multiple hereditary exostoses is extremely variable. In many cases, the disease is asymptomatic. Clinically manifest cases are characterized by uncontrolled exostic growth occurring near the growth plate of bone ends and covered with cartilage.

The bones deform, causing the legs, arms, hands, feet, toes, or fingers to grow unevenly in length. The multiple exostoses can favor movement restrictions. Generalized short stature is also a possible consequence. Some patients complain of pain, usually associated with nerve compression.

Clinically, different courses are distinguished for the disease. According to Pedrini, the MHE is divided into three parts:

  • In class 1, the tumors do not cause any deformities or functional limitations, since there are usually fewer than five exostoses.
  • Class 2 multiple cartilaginous exostoses is associated with deformities but no functional limitations.
  • Deformities with functional limitations characterize class 3.

The number of exostoses varies from case to case. This means that the accompanying pain and impairment symptoms are also extremely variable.

Diagnosis & course of disease

The bone tumors of multiple cartilaginous exostosis are not present at birth, so the diagnosis is typically not made until the age of 12 years. Since the exostoses in many cases result in neither pain nor impairment, a later diagnosis is also conceivable. Diagnosis focuses on imaging methods such as X-ray imaging, with a biopsy usually being taken to assess the tumors.

The histological analysis proves the benign nature of the tumors. In case of doubt, a molecular genetic analysis can be carried out, which provides evidence of the causative mutations. However, this analysis is sometimes very time-consuming. The prognosis of the patient depends on the severity of the disease in the individual case. In cases of severe exostosis, the therapeutic results are often unsatisfactory.


In most cases, those affected by this disease suffer from very severe limitations in movement. As a rule, there is also short stature, which has a very negative effect on the quality of life of the patient. Furthermore, there can be limitations in everyday life, so that the person concerned is dependent on the help of other people in everyday life.

It is not uncommon for pain to occur, which continues to impair everyday life. Those affected also suffer from sleep problems and sleep disorders if the pain also occurs at night in the form of rest pain. In most cases, early diagnosis and treatment is not possible. However, since the tumors are usually benign, they do not primarily pose a particular risk to health.

For this reason, treatment usually only takes place if the disease leads to severe limitations or pain in everyday life. There are no particular complications and there is no reduction in life expectancy. However, in many cases, patients are dependent on physiotherapy.

When should you go to the doctor?

Swelling or growths on the bones are uncommon. If they appear after a bruise or a fall, they can often heal spontaneously. If the symptoms have disappeared after cooling or a sufficient night’s sleep, a doctor is usually not needed. If the irregularities persist or increase in intensity, a doctor should be consulted as there is a disease that requires treatment.

If there are disturbances in the movement sequences, limitations in general mobility or problems with joint activity, a doctor is needed. If pain occurs, there is an increased need for action. Taking pain medication independently is generally not recommended. Due to possible risks and side effects, medication should only be taken in consultation with the doctor treating you.

Bone deformities, poor posture and muscle tension should be examined by a doctor. If participation in social and community life decreases due to the symptoms, if everyday obligations can no longer be fulfilled or if usual sporting activities can no longer be carried out, a doctor is needed.

Inner restlessness, behavioral problems, changes in the complexion and sleep disorders must be examined and treated. Emotional and mental stress, anxiety or severe weight changes are signs of health impairment. The person concerned needs medical help so that the symptoms can be alleviated.

Treatment & Therapy

As long as multiple cartilaginous exostoses show no symptoms, treatment of the patient is not absolutely necessary. A causal treatment cannot take place anyway, since the genetic mutation is irreversible. This means that only symptomatic treatment options are available for patients with hereditary exostoses.

These therapeutic approaches are usually only carried out when the exostoses impair the mobility and everyday life of the patient or severe pain restricts the quality of life of those affected. In such cases, the exostoses are surgically removed invasively. The surgeon is generous in this procedure.

The more he removes, the less likely it is that recurrences will occur. If the exostoses in old age promote secondary diseases such as arthrosis, the use of prosthetic joints may be necessary. If there are extreme pain symptoms, the patient’s quality of life may be improved with pain-relieving medication. In some cases, physiotherapy is used to combat the movement restrictions.

Outlook & Forecast

The prognosis for multiple cartilaginous exostoses varies. It depends on the willingness of the benign tumor to grow and the individual symptoms. The disease usually accompanies patients throughout their lives. A progress check takes place regularly. This can represent a psychological burden due to the unpredictability of the onset of the disease. In the worst case, those affected suffer restrictions in their quality of life. Pain and movement difficulties characterize everyday life. Because of the possible malignant transformation, the multiple cartilaginous exostoses can also shorten lifespan. Statistically, this occurs in five percent of all cases.

The disease is diagnosed in roughly equal proportions in both sexes. Most patients are still children when they are diagnosed and are in their twelfth year of life. The multiple cartilaginous exostoses stop developing at the end of the physical growth phase. If they continue to grow into adulthood, this speaks for a malignant degeneration and thus an unfavorable prognosis.

In therapeutic practice, it appears problematic that multiple cartilaginous exostoses form recurrences. Therefore, surgical interventions often lead to unsatisfactory results. This is also due to the fact that many patients have more than twenty exostoses.


Multiple cartilaginous exostoses are hereditary exostoses. For this reason, genetic counseling in the family planning phase is one of the few ways to prevent the disease. However, the occurrence of the decision not to have children cannot be completely ruled out, since new mutations could also lead to the disease.


When growth is complete, the development of new exostoses usually also ends, so that the disease no longer worsens from this point in time. Even if all functional restrictions have been eliminated by physiotherapy and surgical interventions, regular checks should still be carried out. If an exostosis continues to increase in size or develops again, this is an indication of a degeneration that makes a new treatment necessary.

Some consequences of the multiple cartilaginous exostoses accompany the patient for a lifetime. Differences in leg length or axis deviations in the joints must be treated consistently with orthoses and physiotherapy in order to prevent secondary diseases such as arthrosis or other signs of wear and tear. In general, an active lifestyle with regular exercise is recommended.

This preserves, sometimes even improves, the mobility of restricted joints. In the case of severe limitations, joint-gentle sports such as swimming or walking are indicated. Strength training strengthens the muscles that support deformed joints and thus relieve them.

The psychological consequences of multiple cartilaginous exostoses should not be underestimated either. Due to their differences, children in particular often experience exclusion and bullying. Psychotherapy adapted to the symptoms or visiting self-help groups can help to gain positive experiences.

You can do that yourself

Surgical corrections are contraindicated until the end of puberty and the growth phase, as they trigger even stronger bone growth and thus deterioration.

In order to alleviate symptoms caused by the illness up to this point in time, relatives have various options. Intensive physiotherapy and medical massages have proven to be soothing even in the case of significant movement restrictions and can, under certain circumstances, make the symptoms disappear completely. The exercises used can also be continued at home.

In order to achieve an improvement in the quality of life, the pain and the associated lack of sleep must first and foremost be combated. Mattress pads and chair pads provide good padding and take the pressure off the aching ganglions. Many of those affected also suffer from a significant worsening of their symptoms in the colder months of the year. Warming gel packs, hot- water bottles or special heat-retaining heating pads provide quick relief. Warming cuddly toys for the microwave have also proven useful for smaller children. Electrically operated heating blankets are not recommended, as they harbor the risk of overheating and can lead to fires in the home.

Parents must ensure that children are given access to the prescribed painkillers at school if required. Ideally, these are placed directly in the classroom. A table in which each intake is briefly documented helps to avoid an overdose.