Which bones are frequently affected?

Non-ossifying fibroma is a bone formation disorder and therefore particularly affects bones that grow strongly. The long tubular bones are most frequently affected. These include the bones of the upper and lower arms and the upper and lower legs. Over ninety percent of cases affect the lower extremities, i.e. the legs. As they continue to grow, the ossification is usually made up for and no therapy needs to be initiated.

Imaging of a non-ossifying fibroma

Radiological imaging can detect the non-ossifying fibroma as a random finding. Due to the classic appearance, the diagnosis can be given with a high degree of certainty and in rare cases, further imaging or a biopsy is suggested. The lesion is usually located directly above the periosteum and is a hollowing and thinning of the corticalis (= compact bone layer located directly below the periosteum).

In some places no cortical bone is visible at all. The boundary to the spongy interior of the bone, the cancellous bone, is smooth and sharp and is characterized by increased connective tissue. The non-ossifying fibroma appears as irregularly large lobules, which appear significantly darker in the X-ray image than healthy bone.

In most cases, the non-ossifying fibroma does not cause any discomfort and is therefore almost always a chance finding in the X-ray image in other cases. The non-ossifying fibroma appears as a brightening in the X-ray image. It is a cluster-shaped, brighter area, usually visible in the long tubular bones.

The site is sharply defined, which is a sign of its benignity.In the case of a known non-ossifying fibroma, regular x-ray checks should be performed to observe the regression in growth. The MRI is a high-resolution way to evaluate different body structures. The advantage of MRI over conventional X-ray diagnostics is that there is no radiation exposure.

Even in MRI, a non-ossifying fibroma can be a random diagnosis. With a known non-ossifying fibroma, regular check-ups are necessary, but these are always associated with radiation exposure. This can be prevented with MRI controls. MRI examinations are significantly more expensive than conventional X-rays and are therefore only approved by health insurance companies in exceptional cases.