What is a Bone Island?

Mary McMahon
Mary McMahon

A bone island is a benign growth of bone or cartilage inside a bone, usually within the marrow. It shows up on a medical imaging study, such as an X-ray, as a point of increased density and is believed to be caused by overproduction of bone or cartilage cells. Terms such as enostosis and enchondroma may be used to refer to a bone island. Often, these growths are diagnosed while a patient is being evaluated for another condition.

A diagram of the anatomy of a bone, showing the bone marrow.
A diagram of the anatomy of a bone, showing the bone marrow.

Bone islands can be congenital or developmental. In many people, they cause no ill effects and the patient may be unaware of the bone island or bone islands in the body. Sometimes, however, they can cause pain, especially after exercise. People who experience bone pain usually seek medical treatment for it and the bone island will be diagnosed in the process of evaluating the patient. An orthopedic doctor is usually involved in the diagnosis and treatment of a patient with a bone condition and an oncologist may be involved as well.

Bone islands commonly occur in the hip.
Bone islands commonly occur in the hip.

While bone islands are benign, other conditions that are not benign can look like a bone island at first glance. When such growths are identified, a doctor will usually recommend additional diagnostic testing to find out exactly what is going on. The doctor does not want to miss something like a malignant tumor. Patients will also be asked about any symptoms they may have experienced and how long they have noticed those symptoms, as this information can be key to determining whether an irregularity in a medical imaging study is a bone island or something else.

A bone island can be detected by a bone density scan.
A bone island can be detected by a bone density scan.

Common locations for bone islands include the hip, the fingers, and the thigh. In addition to growing in people, these growths can also be found in animals, especially dogs and horses. A review of the images can often reveal whether or not the growth is bone or cartilage, in addition to showing the precise location and extent of the growth. Usually, images are kept on file so they can be compared with new images on periodic checkups to determine whether or not the growth is changing.

A bone island may be discovered on an X-ray.
A bone island may be discovered on an X-ray.

Sometimes, these growths can become cancerous. People with certain genetic conditions are at risk of cancers of the bone, and a bone island can develop into a malignant tumor in these patients. Someone who is at risk may be monitored for any signs that the growth is behaving abnormally. Options for treatment can include surgery to remove the growth if it is causing pain or it becomes malignant.

In some cases, a malignant tumor may be confused with a bone island so an oncologist is often involved in the diagnosis.
In some cases, a malignant tumor may be confused with a bone island so an oncologist is often involved in the diagnosis.
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments


I have 3cm bone island on my tailbone and it's very painful. Is there any treatment for this ?


How serious is a 1cm sclerotic region of bone in the right iliac wing consistent with a bone island? I was having constipation problems and they saw it in an X-ray. I'm a 59 year old male.


I was diagnosed with benign bone island recently by my oncologist (had breast cancer four years ago)

I was advised to see him again in six months' time for a check up. Advice, please.


My husband has bone island in his pelvis. He was complaining of pelvic pain when the doctor ordered a scan to make sure it was not his appendix. He was told that he had nothing to worry about but he never consulted an oncologist. He is fine so far.


I have a bone island on my right shoulder. I will have it surgically removed sometime next month. How long does it takes to heal up? I will be joining the marines pretty soon.

My bone island pain aches after activities, and I cannot sit still for more than 15 minutes. Driving is a pain and a half. It's also difficult to sleep, and I cannot lift as heavy as I used to because benching makes it ache.


My husband has been diagnosed with prostate cancer. We just got back the final report from his bone scan and ct scan. The ct scan said no (definite) metastasis. However, they said he has a 2.5-cm segment ll and 1.8 cm caudate lobe liver hypodense lesions (likely cysts or biliary hamartoma.) Also, a 1.3-cm left kidney hypodense lesion (likely cyst.) There is dependent atelectasis in the lung basis. Also, a small sclerotic focus on left femoral head (likely bone island). This just seems like too much going on and we are afraid of metastasis.

Could someone please explain this? He has upper stomach pains, pains in his lower back and hips. He has really not been feeling well for a while now. Please, any advice as to what to do next? By the way, he does not see the oncologist/urologist until April. We have had no discussions with him about these findings as of yet.


I was just diagnosed with a bone island on my knee.It is painful after activity The doctor wants to x-ray again in four months. Not to overreact, but if it is something more serious, shouldn't it be looked at sooner?


when i get my medical results they found that i have a bone island in my right rib? is that dangerous? I'm 18 years old.


i got a bone scan done for my hip joint and the first diagnosis was an avecular necrosis stage 1, but when the bone scan was shown to the orthopedic surgeon he felt that it was a bone island. how can one tell the difference between a bone island and an avecular necrosis stage 1?


I have bone island and am having pain in my upper left arm. so much pain also burns like fire. Does anyone know any treatment for bone island?


Can you tell me what the difference between a bone island and an osteoma is?

I know that an osteoma is a type of bone growth, but I wasn't sure if it was the same kind of growth as a bone island or not.

Do you know?


Rarely, a form of cancer called a chondrosarcoma can present with symptoms similar to a bone island. Chondrosarcoma is a cancer of the cartilage, and about 25% of bone cancers originate as a chondrosarcoma. Most of the time chondrosarcoma appears in older people, but it can affect people of any age.

The symptoms of chondrosarcoma are similar to those of a bone island: swelling and localized pain. The pain is usually worse at night, and is dull rather than sharp in nature.

Most of the time symptoms last up to two years before people get them checked out.

Though it's easy to mistake the symptoms of chondrosarcoma for something else, and most of the time such symptoms do not indicate chondrosarcoma; you should still ask your doctor to check it out if you've been having symptoms like this for a long time.

Chances are that it's nothing serious, but it's still better to get it checked out just in case, as most bone cancers go undiagnosed until it's too late for effective treatment.


I had a friend who was recently diagnosed with a bone island in her femur -- the way they found out about it was actually pretty interesting. She had been in a car accident, and they were X-raying her leg to make sure she was OK, and poof, enostosis (bone island).

It hasn't interfered with her health before, so they're just leaving it for the time being, but it made me wonder just how many people actually have bone islands without knowing it.

I guess that's one of the benefits of those full-body scans...but I think I'd rather not know, unless it was dangerous or something.

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