Radiographic Features Of Fibrous Dysplasia

Radiographic Features Of Fibrous Dysplasia

Question. Write a short note on the radiographic appearance of fibrous dysplasia.
Or
Write a short note radiographic features of fibrous dysplasia.
Answer.

Fibrous Tissue Lesion Showing Predominance 

• Early lesions appear radiolucent with ill-defined borders.
• Margins of the lesion are well defined and tend to blend with the surrounding bone.
• Lesion can be unilocular, but sometimes bony septa are apparent, forming an impression of a multilocular cavity.
• Margins of radiolucent area are surrounded by a wide band of increased density, which is granular in appearance.
• Loss of lamina dura is seen.
• Presence of resorption of roots.

Radiographic Features of Fibrous Dysplasia: Diagnosis and Imaging

Lesion Showing Mixed Appearance

• Since the lesion consists of a distribution of fibrous as well as osseous tissue, there is a presence of mixed, i.e., radiopaque and radiolucent appearance.
• New bone takes the form of small opacities of poor density. When these become large, they appear granular.

Mature Radiopaque Lesion

• Here orange-peel appearance is present. Normal bone is replaced by a stippled appearance, which looks like a ring of orange. Teeth get displaced over the affected area.
• As the disease affects the mandible, its vertical depth is increased, and the inferior border seems to be a ribbon-like cortex. In various cases, a localized area present at the cortex becomes lost, and there is presence of smooth, curved projection is seen at the inferior margin of the mandible. This is known as thumb thumbprint appearance.
• As the maturation of disease progresses, bony trabeculae, which are dysplastic, increase both in size and number. This gives a smoky, mottled appearance.
• Another characteristic appearance is of ground glass, also known as granular. It can show areas of whorled amorphous, partially calcified materials, which are well circumscribed.

Fibrous Dysplasia Radiographic Findings and Imaging Techniques

Obisesan et al Radiographic Classification of Fibrous Dysplasia Lesions

• “Paeu d’orange” or orange peel: Here, alternating areas of granular density and radiolucency give a radiographic appearance resembling to peel of the orange.
• Whorled plaque-like type: Here, the matrix of well well-circumscribed lesion consists of plaques of amorphous material of intermediate radiodensity, which on close examination are seen to be arranged in a whorled fingerprint appearance.
• Diffuse sclerotic type: Lesions are seen as homogeneous dense areas, which merge with normal bone.
• Cyst-like type: Here, the lesion is radiolucent, unilocular or more often, multilocular with well-defined margins.
• Pagetoid type: Here affected area of bone markedly expands and shows alternating areas of radiopacity and radiolucency, as seen in Paget’s disease
• Chalky type: It is a well-circumscribed lesion that consists of an amorphous, dense, radiopaque material.

Radiological Diagnosis of Fibrous Dysplasia: X-rays and CT Scans

Fibrous Tissue CT Features

• It evaluates the extent of facial lesions, mainly the orbit.
• CT shows expansion of involved bones in a heterogeneous pattern with scattered or confluent islands of bone formation.
• In the dense lesions, CT attenuation values reach up to 34 to 513 Hounsfield units.