Monostotic fibrous dysplasia
Rare bone disorder replacing normal bone with fibrous tissue in one bone.
Monostotic fibrous dysplasia is a form of fibrous dysplasia where only one bone is involved, comprising a majority of cases (approximately 70–80%). It is a rare, congenital, noninherited, benign anomaly of bone development characterized by the replacement of normal marrow and cancellous bone by immature bone with fibrous stroma, which can cause painful swellings, bone deformities, and increased fragility leading to fractures.
- Field
- Medicine (bone disease)
- Known for
- Rare bone disorder affecting a single bone, most often the ribs, proximal femur, tibia, craniofacial bones, or humerus
- Frequency
- 70–80% of fibrous dysplasia cases
- Sex distribution
- Equal frequency in both sexes
- Typical age of onset
- Late first and early second decades
- Common sites
- Ribs (28%), proximal femur (23%), craniofacial bones (10-25%), humerus (10-25%)
Lore & Background
Monostotic fibrous dysplasia is a congenital, noninherited anomaly that develops early in life, with lesions frequently identified late in the first and early second decades. It occurs with equal frequency in both sexes. The condition involves the replacement of normal marrow and cancellous bone by immature bone with fibrous stroma, leading to painful swellings, bone deformities, and abnormally fragile bones prone to fracture.
Reader's Guide
Monostotic fibrous dysplasia is significant as the most common form of fibrous dysplasia, accounting for 70–80% of cases. It is a rare, benign bone disorder that typically presents asymptomatically, often discovered incidentally or through symptoms such as pain, swelling, or pathologic fracture. Lesions usually enlarge in proportion to skeletal growth and remain active only until skeletal maturity. Importantly, monostotic fibrous dysplasia does not convert into the polyostotic type. The condition most frequently affects the ribs (28%), proximal femur (23%), tibia, craniofacial bones (10-25%), and humerus (10-25%). Its legacy lies in its distinct clinical course and the need for accurate diagnosis to differentiate it from other bone lesions.
Did You Know?
- Monostotic fibrous dysplasia comprises approximately 70–80% of all fibrous dysplasia cases.
- The condition most often affects the ribs (28%) and proximal femur (23%).
More in Genetic disorders with no OMIM 1-24
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