Adamantinomas are rare, slow growing malignant bone tumors, which occurs almost exclusively in the long bones.
Adamantinoma is a rare type of tumor and till date, the origin remains a controversial topic. The tumor was first described by Fischer in 1913  and till date, less than 300 cases have been reported. The tumor occurs almost exclusively within the long bones and in 80% of cases, tumors occur in the tibia. The most commonly affected is the diaphyseal region.
The etiology of the tumor is not known and this has added to the controversy surrounding its origin.
The condition is very rare and so, less than 300 cases have been recorded in the past century . Of the documented cases, it has been established that the condition occurs majorly in young adults who are 20-40 years of age.
Adamantinomas are classified into two main types, the classic and differentiated. Classic adamantinomas is seen in patients already older than 20 years of age but differentiated adamantinomas happen in patients younger than 20. Additionally, these two classifications have distinctive radiographic and histologic differences.
Adamantinoma patients often show varying signs and symptoms. Generally, they report swelling and pain. Since the tumor grows rather slowly, patients often describe discomforts that may have lasted for months or years. Even though it is difficult to figure out an accurate mortality statistics due to the rarity of the tumor, there is 10% 10-year survival rate . When faced with this tumor, medical professionals carry out surgeries which may include either marginal or en bloc resection. Traditional therapy and chemotherapy have not proven effective regarding the effective treatment of the disorder.
In 25% of cases reported, adamantinomas metastasized into the lungs. This is why long-term followup is highly recommended . With negative margin excision, recurrence is rarely recorded. Majority of children treated surgically for adamantinoma have very positive long term outlook. Their 10 year survival rate is placed around 85%.
One of the most common traits of this tumor is its predilection for the long bones. It occurs here in 97% of cases. On the long bones, it focuses on the tibia in 80% -85% of cases. It is therefore its most characteristic clinical feature . In 10% to 15% of cases, the lesion is seen in the ipsilateral fibula. Statistically, this tumor remains prevalent in the tibia but other limb bones have been involved. The involvement of several short bones has been reported on rare occasions as well. In other of decreasing frequency, some other bones that have been involved at appoint or the other includes:
Only six case of spinal adamantinoma have been reported till date . There have also been rare reports of adamantinomas arising exclusively from the pretibal soft tissues without any bony involvement. The initial symptoms of adamantinomas are usually indolent and non-specific.
They are also dependent on the location and extent of the disease. The onset of the disease is insidious and the course shows a slow progressive character.
In many cases the patients endure years of pain before seeking medical attention. In 60% of reported cases, trauma is common place. Apart from the pain reported, many patients also show swelling. The swelling may also be there without the pain.
Due to the involvement of the anterior tibial surface, patients may present bowing deformity of the fibia . In as many as 23% of patients, pathological fracture was present. Other rare cases show paraneoplastic hypercalcemia (linked with tibial adamantinoma) and pulmonary metastasis. In addition to the pain spinal lesions may be manifested by neurologic symptoms.
Radiographs are used for confirmatory purposes and they show many lucent lesions that are sharply circumcised. There is often interspersed sclerotic bone in mid tibia. Some lesions also destroy cortex. Bowing of the tibia may be seen as well. The radiographic evolution of lesions often proves helpful in diagnosis as lesions continue to grow and erode through the cortex . Unlike what is seen in most primary bine tumors, adamantinoma doesn’t show any periosteal reaction.
Histological studies are carried out as well and they show fibrous and epithelial tissue in gland like pattern characteristically. Epithelial and mesenchymal cells will be visible too as well as nests of epithelial-like cells arranged in palisading or glandular pattern. A background of fibrous stroma is also common.
Generally, treatment involves wide resection or amputation. During the course of the disease metastases may occur. This occurs in 30% of cases even though it is rare at presentation. Prognosis and response to treatment is great but the chances are lower when a wide surgical margin cannot be obtained.
Chemotherapy does not work as the tumor is not sensitive to radiation . The only time when chemotherapy is deployed is when the cancer has spread to the lungs or other sensitive organs.
There are no proven ways to prevent this but regular exercise of the lower extremities and bone friendly nutrition is recommended.
Patients are advised to cooperate with medical personnel and accept any procedures recommended by them. Adamantinoma doesn’t respond to chemotherapy, radiation etc. So surgery is the treatment method in most cases . The different types of surgery are:
If the adamantinoma reoccurs, more surgery will be required.
Healthy individuals are encouraged to immediately report any pain in the lower extremities that have lasted more than a week. This condition must not be confused with arthritis.