Fibrous dysplasia is a bone lesion in which a section of normal bone tissue is replaced by connective tissue with the inclusion of bone trabeculae. It belongs to the category of tumor-like diseases, can be local or widespread, affect one or more bones. It is manifested by pain, deformation, shortening or lengthening of the segment and pathological fractures. The diagnosis is made on the basis of radiography, MRI, CT and other studies. Treatment is usually surgical – resection of the affected area of the bone with replacement of the defect.
ICD 10
M85.0 M85.4 M85.5
Meaning
Fibrous dysplasia (Lichtenstein’s disease) is a systemic lesion of the skeleton. Symptoms are usually detected in childhood, but a later onset is also possible. The literature describes cases when monossal fibrous dysplasia was first diagnosed in people of retirement age. Women get sick more often than men. It is possible to degenerate into a benign tumor; malignancy is rarely observed.
The disease was first described in the first half of the 20th century. In 1937, Albright described multifocal fibrous dysplasia, combined with endocrine disorders and characteristic skin changes. In the same year, Albrecht described multifocal dysplasia in combination with premature puberty and fuzzy skin pigmentation. A little later, Jaffe and Lichtenstein investigated single-focal lesions and published conclusions about the causes of their occurrence.
Causes
Fibrotic dysplasia belongs to the category of tumor-like diseases, but is not a true bone tumor. It occurs due to the improper development of osteogenic mesenchyma (tissue from which bone is subsequently formed). The causes of development are not clear, a genetic predisposition is not excluded.
Classification
In traumatology and orthopedics, there are two main forms of fibrous dysplasia: monossal (with damage to one bone) and polyossal (with damage to several bones, usually located on one side of the body). The polyossal form develops in childhood and can be combined with endocrine disorders and melanosis of the skin (Albright syndrome). The monossal form can manifest at any age, endocrinopathies and skin pigmentation are not observed in patients. Russian specialists use the clinical classification of Zatsepin, which includes the following forms of the disease:
- Intraosseous form. It can be monossal or polyossal. Single or multiple foci of fibrous tissue are formed in the bone, in some cases bone degeneration is observed throughout, but the structure of the cortical layer is preserved, therefore there are no deformations.
- Total bone damage. All elements suffer, including the cortical layer and the area of the bone marrow canal. Due to the total lesion, deformations are gradually formed, fatigue fractures often occur. Usually there is a polyossal lesion of long tubular bones.
- Tumor form. It is accompanied by the proliferation of foci of fibrous tissue, which sometimes reach significant sizes. It is rarely detected.
- Albright syndrome. It is manifested by polyossal or practically generalized bone damage in combination with endocrine disorders, premature puberty in girls, violation of body proportions, focal pigmentation of the skin, severe deformities of the limbs and trunk bones. It is accompanied by progressive disorders on the part of various organs and systems.
- Fibrous-cartilaginous dysplasia. It appears as a predominant degeneration of cartilage, transformation into chondrosarcoma is often observed.
- Calcifying fibroma. A special form of fibrous dysplasia, very rare, usually affects the tibia.
Symptoms
Pronounced congenital deformities are usually absent. With the polyossal form, the first symptoms appear in childhood. Bone damage is accompanied by endocrinopathies, skin pigmentation and a violation of the cardiovascular system. The manifestations of the disease are quite diverse, the most constant signs are minor pains (usually in the hips) and progressive deformities. Sometimes the disease is diagnosed only when a pathological fracture occurs.
Usually, in the polyossal form, there is a lesion of the tubular bones: tibial, femoral, fibular, humeral, radial and ulnar. From flat bones, pelvic bones, skull bones, spine, ribs and shoulder blade are more often affected. Often, the lesion of the bones of the hands and feet is detected, while the bones of the wrist remain intact. The degree of deformation depends on the localization of foci of fibrous dysplasia. When the process occurs in the tubular bones of the upper extremities, usually only their club-like expansion is observed. When the phalanges are affected, the fingers are shortened, they look “chopped off”.
The bones of the lower extremities bend under the weight of the body, characteristic deformities occur. The femur is especially sharply deformed, in half of the cases its shortening is revealed. Due to the progressive curvature of the proximal sections, the bone takes the form of a boomerang (shepherd’s crook, hockey stick), the large spit “shifts” upwards, sometimes reaching the level of the pelvic bones. The neck of the hip is deformed, lameness occurs. The shortening of the hip can be from 1 to 10 cm.
When a focus is formed in the fibula, there is no deformity of the limb, when the tibia is affected, there may be a saber-shaped curvature of the lower leg or a slowdown in the growth of the bone in length. Shortening is usually less pronounced than with a focus in the femur. Fibrous dysplasia of the iliac and sciatic bones causes deformation of the pelvic ring. This, in turn, negatively affects the spine, provoking posture disorders, scoliosis or kyphosis. The situation is aggravated if the process simultaneously affects the hip and pelvic bones, since in such cases the axis of the body is further disrupted, and the load on the spine increases.
The monossal form proceeds more favorably, there are no extraosseous pathological manifestations. The severity and nature of deformities vary greatly depending on the localization, the size of the lesion and the features of the lesion (total or intraosseous). There may be pain, lameness and increased fatigue after loading the affected segment. As with the polyossal form, pathological fractures are possible.
Diagnostics
The diagnosis is made by an orthopedic traumatologist based on the clinical picture and X-ray examination data. At the initial stage, X-rays in the area of the diaphysis or metaphysis of the affected bone reveal areas that look like frosted glass. Then the affected area acquires a characteristic speckled appearance: foci of compaction alternate with areas of enlightenment. The deformation is clearly visible.
If a single focus is detected, it is necessary to exclude multiple bone lesions, which may be asymptomatic at the initial stages, therefore patients are referred for densitometry. In the presence of suspicious areas, radiography is performed, if necessary, a CT scan of the bone is used.
It should be borne in mind that fibrous dysplasia, especially monossal dysplasia, can present significant difficulties in the diagnostic process. With mild clinical symptoms, long-term dynamic monitoring is often required. To exclude other diseases and assess the condition of various organs and systems, consultations of a phthisiologist, oncologist and therapist may be required. In some cases, an examination by a cardiologist, endocrinologist or other specialists is indicated.
Treatment
Treatment is mainly surgical – complete segmental resection of the affected area of the bone within healthy tissues and replacement of the defect with a bone graft. In case of a pathological fracture, the Ilizarov apparatus is applied. In case of multiple lesions, preventive measures are carried out aimed at preventing deformations and pathological fractures.
Prognosis and prevention
The prognosis for life is favorable. In the absence of treatment, especially with the polyossal form, gross crippling deformities may occur. Sometimes the foci of dysplasia degenerate into benign tumors (giant cell tumor or non-ossifying fibroma). Several cases of malignant degeneration into osteogenic sarcoma have been described in adults. There is no specific prevention due to the unclear etiology of the disease.
Literature
- Surgical Treatment of Fibrous dysplasia in the Maxillary Bone of a 12 Year-Old Girl: A Case Report. Samieirad S, Momtaz MM, Mohtasham N, Mohammadzadeh F, Ebrahimzadeh N, Tohidi E. World J Plast Surg. 2021 Sep;10(3):126-133 link
- Response to Zoledronic Acid Infusion in Children With Fibrous Dysplasia. Tripathy SK, Swaroop S, Velagada S, Priyadarshini D, Das RR, Satpathy AK, Agrawal K. Front Pediatr. 2020 Nov 24;8:582316. link
- A rare case report of craniofacial fibrous dysplasia. Chandavarkar V, Patil PM, Bhargava D, Mishra MN. J Oral Maxillofac Pathol. 2018 Sep-Dec;22(3):406-409. link
- Treatment of Girls and Boys with McCune-Albright Syndrome with Precocious Puberty – Update 2017. Neyman A, Eugster EA. Pediatr Endocrinol Rev. 2017 Dec;15(2):136-141. link
