Presentation on theme: "FIBROUS DYSPLASIA: IMAGING CHARACTERISTICS"— Presentation transcript:
1 FIBROUS DYSPLASIA: IMAGING CHARACTERISTICS H. ZAGHOUANI BEN ALAYA, A.BEN ABDALLAH,S. YAHYAOUI, S. MAJDOUB,T. RZIGUA,L. BEN CHRIFA,H. AMARA, D. BEKIR, CH. KRAIEMImaging department, Farhat Hached Hospital, Sousse, Tunisia
2 INTRODUCTIONFibrous Dysplasia (FD) of bone is a rare non-inheritable congenital disease.It is characterized by a focal proliferation of fibrous tissue in the bone marrow leading to osteolytic lesions deformities and fractures.FD can be presented in a monostotic or polyostotic form.The complications are represented mainly by bone deformities and nerve compression
3 IntroductionThe imaging appearance is often characteristic and allows in combination with the clinic findings the diagnosisAuthors attempted to highlight the interest of imaging in the diagnosis of FD.The literature is reviewed to delineate radiologic features of monostotic and polyostotic fibrous dysplasia.
4 PATIENTS AND METHODS Retrospective study of 7 cases. FD was monostotic in 4 cases and polystotic in 3 casesIt involves proximal femurs in 1 case, ribs in 2 cases4 reported cases were craniofacial form and the involved bones were maxilla (n= 1), sphenoid (n = 1), temporal (n= 1), and frontal bone (n= 2)Only 2 cases showed involvement of spine.
5 CASE N°1A 19-year-old boy presented to his doctor because of shoulder pain of 1 year’s duration.b(a) Well-defined lytic lesions of the humerus and both bones of the forearm, which at times appear multilocular and expansilewith thinnes but unruptured cortical(b) CT showed in the medullary cavity replacement of cancellous bone with a homogeneous hyperdense beach responsible for thinning of the corticala
6 Case n° 1 a b c e d Polyostotic FD MR coronal images: *The lesions has low signalintensity on T1-weighted MR image (a ), high weighted intensity on T2 (b)* T1-weighted MR image with fat saturation and after administration of gadolinium (c ) show that there is mild to moderate heterogeneous enhancement of lesion.PolyostoticFDabc*The same patient has cervical MRI for cervicalpain that shows a lesion of the vertebral hemibody of D1which has low intensity signal on T1 without cortical lysisor soft tissue abnormality on sagittal T1-weighted MR image (d).* T1-weighted MR image with fat saturation and afteradministration of gadolinium (e ) show that there isan intense enhancement of lesion.ed
7 CASE N°2A 24-year-old man who presents with a meningeal syndrome. A cerebro-medullar MRI was indicatedMonostoticFD of spinec*Sagittal T2-weighted MR image (a ) shows a low signallesion of the vertebral body of D1 with an intenseand homogene enhancement of the lesion onT1-weighted MR image (b ).*CT scan reveals increased bone density of D1 (c ).ab
8 CASE N°3A 27-years-old woman , consultsfor diplopia lasting for 6 months. the clinical examinationfound left convergent squint and paralysis of the V and VI cranial nerves.abcCoronal MR images show a lesion interesting the left greater wing of sphenoid. This lesionhas an intermediaire signal on T1 (a) , a low signal on T2 (b) and present an intenseenhancement on contrast-enhanced T1-weighted MR image with fat-saturation (c ).
9 Case n° 3Base of the skull(sphenoid) FDAxial and coronal CT scan show fibrous dysplasia involving body, the left greater wing of sphenoid bone (blue arrows). Note expanded left pterygoid process (arrowhead) and inflammatory changes in left sphenoid sinus (*).
10 CASE N°4A 35-year old woman who consulted for left frontal and orbital swellingCranio-facial FDacb*Axial T1-weighted MR (a ) and coronal T2-weighted MR (b) images reveal expansile lesion, with low signal intensity involving rleft frontal and parietal bones* Axial T1-weighted MR image with fat saturation and after administration of gadolinium (c ) show that there is mild to moderate heterogeneous enhancement of lesion.
11 CASEN°5A 12-years old boy who presented a ptosis of the left upper eyelidCranio-facial FDabc*Axial CT scan (a) show thickening and increased fronto-orbital leftbone density.*Coronal MR images show a lesion interesting left roof of orbit.This lesion has a low signal intensity on T1 (c) and T2 (b) .*T1-weighted MR image after administration of gadolinium (d ) showthat there is intense and heterogeneous enhancement of the lesion.d
12 DISCUSSIONFibrous dysplasia (FD) is a congenital and noninherited benign bone diseaseFD has been regarded as a developmental skeletal disorder characterized by replacement of normal bone with benign cellular fibrous connective tissue.It affects both sexes with a slight female predominance and is diagnosed between 5 and 30 years on average
13 DiscussionIt affects both sexes with a slight female predominance and is diagnosed between 5 and 30 years on averageThe lesions grow with the child, stabilize after puberty and appear exceptionally in adulthoodFD can affect one bone (monostotic form) or multiple bones (polyostotic form), and the latter may form part of the McCune-Albright syndrome (MAS) or Mazabraud syndrome
14 Monostotic Fibrous Dysplasia The monostotic form of FD comprises approximately 80% of all casesIt is seen in patients between 10 and 70years old.The most common sites of involvement include the rib, femur, tibia, mandible, skull, and humerusSolitary involvement of other bones is unusualFD of the spine is rare. It most commonly involves the body and adjacent pedicle without particular predilection for a part of the spinal column
15 The skull and facial bones are the affected sites in 10–25% Monostotic Fibrous DysplasiaThe skull and facial bones are the affected sites in 10–25%All bones of the skull and the face may be affectedIt concerns mainly the ethmoid (72%), sphenoid (43%), the frontal bone (33%), maxilla (24%) and less frequently the temporal, parietal, occipital or mandible bone.
16 Monostotic Fibrous Dysplasia Uncomplicated monostotic lesions are generally asymptomatic and usually do not cause significant deformity.As a rule, monostotic fibrous dysplasia does not convert to the polyostotic formlesions do not increase in size over time, and the disease becomes inactive at puberty
17 Polyostotic Fibrous Dysplasia The polyostotic form of FD may involve many or few bones, most commonly the skull and facial bones, pelvis, spine, and shoulder.Polyostotic fibrous dysplasia is often unilateral, and may be bilateral, always asymmetricIt tends to involve larger segments of bone and is frequently associated with fractures and severe deformities.
18 Polyostotic Fibrous Dysplasia Involvement of the skull may cause cranial nerve dysfunction with visual and hearing impairmentAlthough the manifestations of polyostotic fibrous dysplasia may be severe, it does not spread or proliferate and generally becomes quiescent at puberty, but existing deformities may progress
19 Syndromes Associated with Fibrous Dysplasia 1-McCune-Albright syndrome is an endocrinopathy occurring mainly in girls, consisting of the triad of precocious puberty, polyostotic FD, and characteristic cutaneous pigmentation referred to as “café au lait” spots 2-Mazabraud syndrome is the rare combination of fibrous dysplasia and soft-tissue myxomas
20 Imaging findings: radiograh and CT Classically, fibrous dysplasia lesions are intramedullary, expansile, and well defined lesion with thick sclerotic bordersAlthough endosteal scalloping may be present, a smooth cortical contour is always maintainedLesions show varying degrees of hazy density with a ground-glass quality, although some may appear almost completely radiolucent or sclerotic
21 Three types of lesions are distinguished depending on the degree of hazy density : *The ground-glass pattern*The homogeneously dense pattern: increased bone density compared with adjacent normal bone*The cystic variety: At times, a mubtilocubar, cystic lesion with well-defined margins can be seenOccasionally, calcified cartilaginous and osseous foci may be present within the lesion
22 MRI findings The MRI characteristics of FD are variable Typically showing signal intensity that is intermediate to low on T1- weighted imagesIntermediate to high signal on T2-weighted imagesThese high signal intensities on T2- weighted images correspond to nonmineralized areas and regions of cystic changeFibrous dysplasia reveals varying degrees of enhancement after gadolinium infusion.
23 MRI findingsThe fibrous tissues in FD are well vascularized and often show numerous small vessels in the center and large peripheral sinusoids. These histologic features explain why fibrous dysplasia enhances intensely after the injection of contrast material
24 Complications of Fibrous Dysplasia 1-Pathologic fractureThese fractures generally heal normally, but additional fractures may subsequently occur at the same site2-Malignant degeneration of FDComplicates less than 1% of all casesRadiographic findings include cortical destruction and associated soft-tissue massesThe most common malignancies include osteosarcoma, fibrosarcoma, and malignant fibrous histiocytoma.
25 CONCLUSIONFibrous dysplasia is a common benign bone disease existing in monostotic and polyostotic formsComplications, and associations of fibrous dysplasia is important to ensure the accurate diagnosis and appropriate management of this diseaseThe imaging features of fibrous dysplasia are characteristic, although not specific, and depend on the underlying histopathology of a given lesion.