Rare Bone Tumor- Fibrous Dysplasia

Fibrous dysplasia is a bone tumor which is related to a genetic abnormality leading to abnormal bone formation.  Normal bone is replaced by a fibrous tissue.  It can present at any age- young kids, adolescence, or even adulthood.  It is a bone tumor but it is benign growth. Rarely, the tumors can become malignant, but this only happens in about 1 in 20 of kids with fibrous dysplasia.  McCune Albright Syndrome includes kids with fibrous dysplasia, endocrine disorders (such as early puberty), and skin lesions (cafe au lait spots).

Fibrous Dysplasia typically presents in the legs but can occasionally present in the upper extremity, typically the humerus bone.  It may involve only one bone or can involve many bones.  The bone develops abnormally, expands, and can break due to the weakened nature of the bone.  The bone can be painful or the pain can develop from a fracture of the weakened bone  Bones can bow due to the weakening caused by the fibrous tissue of fibrous dysplasia.  X-rays have the classic appearance of ground glass and bone specimens examined under a microscope show a ‘chinese letter’ pattern.

Treatment for fibrous dysplasia depends on many different factors.  Fractures may require surgical treatment although they can heal without surgery.  Bowing of the long bones can cause problems and sometimes has to be addressed with bone realignment (or osteotomy).

Medications called bisphosphonates which may have a role in treatment of fibrous dysplasia.  These come in different forms including pills.  These have been reported to help pain and limit deformity but the true expectations continue to be clarified.

Here is one of our patients followed over time with fibrous dysplasia of the humerus.  The early xrays from 2010 of the left humerus show a fracture, which healed without surgery.  Recent xrays from October 2016 show some progression of the fibrous dysplasia over time.

Early xray from 2010 of patient with fibrous dysplasia
Later in 2010, the humerus fractures due to weakness of bone in fibrous dysplasia.  The bone broke after a fall. 

Healing humerus after fracture in fibrous dysplasia

The most recent xray of humerus with fibrous dysplasia.

Charles A. Goldfarb, MD

My Bio at Washington University

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