What Is an Adamantinoma?
An adamantinoma is a particularly rare, malignant (cancerous) tumor that starts in bones. Among primary bone cancers—also known as bone sarcomas—adamantinomas represent just 1 percent of cases.
Adamantinomas appear most often in men, after their bones have fully developed. The tumors most often form as lumps in the shin bone (tibia). They can also affect the fibula bones (the second bone in the lower leg). Less often, adamantinomas occur in other bones.
Adamantinomas are slow-growing tumors, but they can damage surrounding bone. If they grow large enough, they may eventually invade nearby soft tissues, including muscles. In 15 percent to 20 percent of cases, these tumors metastasize (spread) to other parts of the body, mainly affecting the lungs and less commonly the lymph nodes and other bones.
The Sarcoma Program at Penn Medicine’s Abramson Cancer Center provides one of the nation’s most experienced adamantinoma care teams.
Adamantinoma Symptoms and Warning Signs
Most cancerous bone tumors, including adamantinoma, cause pain. Depending on the location and size of the tumor, you may experience symptoms such as:
- Bone pain from tumor damage
- Difficulty moving the leg, possibly causing a limp
- Noticeable lump on the shin bone
- Odd-looking lower leg with a bowed or curved shin bone
- Swelling and pain near the tumor
What Causes an Adamantinoma?
Researchers do not yet know what causes an adamantinoma. Currently, there isn’t anything you can do to reduce your risk of developing one of these rare tumors.
Studying these tumors is challenging because they are so rare. Unlike some other bone cancers, no evidence exists that adamantinomas run in families or have ties to previous medical treatments.
Adamantinoma Diagnosis
On scans, adamantinomas share similarities with other health conditions that affect the tibia, such as fibrous dysplasia, a bone disorder that forms scar tissue; osteofibrous dysplasia, a rare benign bone tumor; and osteomyelitis, an infection in the bone. So it’s important to get any potential growth thoroughly evaluated by a team with bone sarcoma experience.
Adamantinomas are also closely related to benign lesions in a similar location called osteofibrous dysplasia (OFD). This kind of growth forms along the front of the tibia and occurs in children.
To make an adamantinoma diagnosis, our doctors will ask about any symptoms you’re experiencing and give you a physical exam. They’ll also arrange a series of tests:
Imaging Tests
Imaging tests help us determine if you have a bone tumor and, if so, which kind. These tests also help show the tumor’s size and precise location. They can also show whether any cancer has spread.
Adamantinomas often have a distinct appearance, so traditional X-rays may provide enough information to diagnose these tumors. At times, our team may need to turn to additional imaging such as magnetic resonance imaging (MRI) or computed tomography (CT).
Tumor Biopsy
In addition to imaging, we often recommend taking a sample of the tumor during an image-guided needle biopsy. This sample can help confirm the diagnosis and provide additional information about the tumor. Specialized doctors (pathologists) view the sample under a microscope and also run tests on its cells.
The information we gather from the exam, imaging and biopsy help us stage most adamantinomas—categorizing the cancers to help determine the most appropriate treatment recommendations. This process is done for all bone cancers.
Learn more about sarcoma diagnosis and staging.
Adamantinoma Treatment at Penn
Adamantinomas are often highly treatable. Individual outlook depends on a number of factors, including age, overall health, and whether the cancer has spread. The best treatment results come from teams that see more of these rare cancers.
Adamantinomas are treated with surgical removal. Our team is skilled in the most effective approach, which removes the entire tumor in one piece with a bit of normal tissue on all sides. Complete removal is often enough to cure an adamantinoma. Chemotherapy or radiation therapy typically aren’t used unless the cancer has spread.
Even with appropriate treatment, adamantinomas sometimes recur (return) in the same area of the tibia. To protect your health, we follow you closely after treatment. Regular checkups ensure that if cancer does return, we can treat it quickly.
Learn more about sarcoma treatment from the Penn Medicine team.
Make an Appointment
Please call 800-789-7366 or make an appointment.
The Penn Sarcoma Program offers same-day appointments to patients who have their imaging available. To learn more, call 215-349-8200.