Monostotic fibrous dysplasia is a form of
fibrous dysplasia
Fibrous dysplasia is a disorder where normal bone and marrow is replaced with fibrous tissue, resulting in formation of bone that is weak and prone to expansion. As a result, most complications result from fracture, deformity, functional impairme ...
where only one bone is involved. It comprises a majority of the cases of fibrous dysplasia (approximately 70–80%).
It is a rare
bone disease
Bone disease refers to the medical conditions which affect the bone.
Terminology
A bone disease is also called an "osteopathy", but because the term osteopathy is often used to refer to an alternative health-care philosophy, use of the term can ...
characterized by the replacement of normal elements of the bone by
fibrous connective tissue
Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme derived from the mesoderm the middle embryonic germ layer. Connective tissue is ...
, which can cause very painful swellings and bone deformities, and make bone abnormally fragile and prone to fracture.
A
congenital
A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can ...
, noninherited, benign anomaly of
bone development
A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, and ...
in a single bone, it consists of the replacement of normal marrow and cancellous
bone
A bone is a Stiffness, rigid Organ (biology), organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red blood cell, red and white blood cells, store minerals, provid ...
by immature bone with fibrous
stroma. Monostotic fibrous dysplasia occurs with equal frequency in both sexes and normally develops early in life, with lesions frequently identified late in the first and early second decades. Most patients are asymptomatic, with the diagnosis often established after an incidental finding or with pain, swelling, or fracture. Lesions usually enlarge in proportion to skeletal growth and the abnormal replacement remain active only until skeletal maturity.
Monostotic fibrous dysplasia does not convert into the
polyostotic type. When symptoms are present, they often are nonspecific, including pain, swelling, or pathologic fracture. It most often affects the
ribs
The rib cage, as an enclosure that comprises the ribs, vertebral column and sternum in the thorax of most vertebrates, protects vital organs such as the heart, lungs and great vessels.
The sternum, together known as the thoracic cage, is a semi- ...
(28%), proximal
femur
The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates with ...
(23%),
tibia
The tibia (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it connects ...
, cranio
facial bone
The facial skeleton comprises the ''facial bones'' that may attach to build a portion of the skull. The remainder of the skull is the braincase.
In human anatomy and development, the facial skeleton is sometimes called the ''membranous viscerocr ...
s (10-25%) and
humerus
The humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a roun ...
(10-25%).
See also
*
Polyostotic fibrous dysplasia
Polyostotic fibrous dysplasia is a form of fibrous dysplasia affecting more than one bone. Fibrous dysplasia is a disorder where bone is replaced by fibrous tissue, leading to weak bones, uneven growth, and deformity.
McCune-Albright syndrome in ...
References
External links
Osteopathies
Genetic disorders with no OMIM
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