74 terms

Fibrous Dysplasia & Paget's Disease

Fibrous Dysplasia and Paget's Disease are considered the "Great __" of bone disease.
"Great Imitators"
What are the 3 types of Fibrous Dysplasia?
1) Monostotic FB (70% ~14yo)
2) Polyostotic FB (27% ~11yo)
3) Polyostotic FB w/Endocrine abnormalities aka McCune-Albright Syndrome (3% ~8yo)
Briefly describe Fibrous Dysplasia?
Slow benign progression of bone being replaced by a weaker fibrous type of bone w/poorly formed bony trabeculae
In FD the bone scan is __ due to constant __.
constant bone turnover
T/F FD is often asymptomatic and may present w/pathologic fracture.
What signs are seen w/FD?
1) Shepherd's Crook Deformity
2) Leontiasis Ossea
3) Leg length Discrepancy
4) Expansion of Rib
5) Cafe au Lait Spots
Define Shepherd's Crook Deformity.
Coxa vara (smaller angle) bowing of the proximal femur
Define Leontiasis Ossea.
Enlargement and deformity of the cranial and facial bones
Bowing deformities and pathologic fractures are m/c seen in what type of FD?
Polyostotic FD
Define Cafe au Lait Spots seen with FD
-pigmented skin macules due to increased melanin/proliferation of melanocytes in the epidermis
-irregular margins = "Coast of Maine" appearance
FD has a ground-glass/smokey-foggy matrix that is due to what?
Lack of normal Cortical and Trabecular organization
Note: this causes Endosteal Scaloping
T/F Endosteal Scaloping is seen in both FD and Paget's
-only FD
FD starts in the __ or __ and spreads into the __, while Paget's starts __ and spreads up or down.
-Metaphysis or Diaphysis
The mc etiology of benign rib lesions is?
Monostotic FD
T/F there is no transistion from Monostotic to Polyostotic FD type.
T/F there is a higher incidence of Pathologic fractures and deformities (Shepherd's Crook) in Monostotic FD
-in Polyostotic FD
Breifly define McCune-Albright Syndrome.
-Polyostotic FD with skin pigmentation and early premature sexual development
-Females only
-Prematue irregular menstrual bleeding at 5-6yo
Cherubism is a condition seen in FD patients. Breifly explain.
-Multilocular Cystic lesions with asymmetric distribution in the mandible and maxilla
-Affects Jaws/swelling of lower face and cheeks
-Soap Bubbly expansile cortical thinning with trabeculation
-Regresses during puberty
FD in the skull and maxilla is more __ due to higher concentration of bone spicules
T/F FD can malignant degenerate to Fibrosarcoma?
Monostotic FD is m/c in __ and __.
Ribs, Proximal Femur
Monostotic FD starts where in the bone and spares what on the bone.
-Spares Subarticular Suface
T/F Radiolucency, Loculated trabeculation, ground glass/smokey appearance (thus no trabecular patterns), geographic cystic lesions are seen in Monostotic FD
T/F A thick sclerotic margin aka rind of sclerosis is seen in Paget's, in which Myeloma's or Metastasis does not have.
-seen in Monostotic FD
T/F Endosteal scalloping widening medullary canal, Bone Expansion, NO periosteal reaction unless pathologic fraction are seen Monostotic FD
If only slight or no uptake is seen on bone scan of FD this means you can what?
Rule out FD
Polyostotic FD is m/c in __, __, __, and __.
Pelvis, Extremities, Ribs, and Skull
Polyostotic FD __ the out table of the skull, where Paget's __.
T/F the spine is commonly involved in FD
T/F In Polyostotic FD symptoms are usually from bowing deformities and pathologic fractures.
T/F Shepherd's Crook deformity, a ground glass appearance, endosteal scalloping, loculation of lesions, and pseudofractures along the covex surface of deformed cortex are roentgen findings in Monostotic FD.
-in Polyostotic FD
Polyostotic FD rib lesions cause what sign in the lungs?
Extrapleural sign
T/F Monostotic FD normally invovles the entire shaft of the bone.
-Polyostotic FD
Breifly describe Paget's Disease (aka Osteitis Deformans).
-Osteolysis followed by extensive repeated attempts at repair
-Mostly(90%) Asymptomatic = incidental finding
-Fibula least likely affected
Age range for Paget's disease?
In Paget's pain is from?
1) Microscopic Fx
2) Increased blood flow
3) Joint destruction
4) Mechanical destruction of bone
What is thee Hallmark sign in Paget's?
Bony Enlargement
-Increase in HAT and SHOE size normally seen
-Cortical Thickening
-Medullary Canal stenosis
What 3 deformities are seen in Paget's?
1) Shepherd's Crook deformity
2) Sabre Shin deformity
3) Basilar Invagination
4) Spinal Stenosis
What is Sabre Shin Deformity?
-anterior bowing of the shin
-Fibula not affected
-seen in Paget's
What is Basilar Invagination?
When C2 vertebra migrates in to the foramen magnum causing stenosis
-Brainstem Compression, syringomyelia, obstructive hydrocephalus
-Cranial N. palsies
-Bone incduced Basilar A. Syndrome w(HA, giddiness, vertigo, spinal cord ischemia)
What is seen w/Spinal Stenosis in Paget's?
-Bone expansion leads to compressive neuropathy
-possible Cauda Equina Syndrome
-Distorted soft bones or pathologicFx can = neuropathy
-Leg weakness, Urinary incontinence, sensory problems
-Protrusio Acetabuli
What are some Roentgen sign almost always seen in Paget's?
-Bony enlargement
-Cortical thickening
-Trabecular pattern more promininant (thickening)
-PathologicalFx or pseudoFx
-COTTON BALL/WOOL appearance
-Out of focus non-homogeneous PATCHY sclerotic appearance
T/F in Paget's a lot of times there is a fused appearance of bone, (ie SI, Femur Head)
T/F mc complication in Paget's is pathologic Fx.
-Banana like Fx affecting tubular bones usually weight bearing bones
-Ususally occur during stage 2 or 3
What are PseudoFx?
-Local areas of fibrous tissue replacing demineralized bone
-can result in complete Banana Fx
-Bilateral & Symmetrical lucent bands perpendicular to cortex
What is a Banana Fracture?
Transverse insufficiency fracture through the proximal femoral shaft
T/F Protrusio Acetabuli and leontiasis Ossea are common Paget's
T/F bone scans are "hot" with Paget's
-Due to hypervascularity
-Want to do plain films to confirm
In Paget's the Hip and Knee are commonly affected due to what?
Necrosis that caused articular cartilage resorption and replaced by Pagetic bone = arthrosis
Describe Malignant Degeneration of Paget's and what stage it occurs in?
-mc in femur, then humerus
-mc see Osteosarcoma (usu lytic)
-Stage 4
T/F in Pagets Cannon-Ball/Pulmonary Metastasis to the lungs is common = early death.
T/F Metastatic disease typically doesnt affect Pagetic bone.
Paget's usually has __ periosteal reaction, with soft tissue mass and pathologicFx being __.
-has NO periosteal reaction
Paget's has a definite __ in alkaline phosphatase which can be a ddx to FD, which is less seen in.
-20x normal
Pathology of Paget's?
-Bone destruction replaced by fibrous tissue and osteiod that may calcify
-Possible hemorrhage and necrosis
-Hypervascularity of bone
-Destruction and repair occur repeatedly, reulting in the "Mosaic Structure of Paget's"
4 Stages of Paget's Disease?
1) Osteolytic/Destructive
2) Destruction and Repair (M/C)
3) Rare (can occur outside of other stages in itself)
4) Malignant Transformation
Pagets of the Skull is know as__ and is seen in what stage?
-Osteoporosis Circumscripta
-Stage 1
Describe Stage 2 Paget's
-MC stage
-Destruction and Production (Repair) of bone
-Cheap fibrous bone replacing destroyed bone
-Cortical thickening
-Increased radiopacity and enhanced trabecular patterns w/interspersed radiolucent areas
-Bone Enlargement
Cotton Ball/Wool appearance is seen in which stage of Paget's?
Stage 2
Seen in Paget's, what is a Picture Frame Vertebra?
Enlargement/cortical thickening of vertebra with sclerosis more prominent at the endplates
Describe "Blade of Grass" seen in Paget's
Abnormal lucency in th distal femur w/a flame-shaped or "Blade of Grass" shaped proximal margin
-Due to advancing lytic phase of Paget's
What is seen in Stage 3 Paget's?
-Sclerotic or IVORY stage
-usu seen in innominate or vertebrae
-may or may not have bony enlargement
What are all the radiographic findings in Paget's Disease?
1) change in bone density
2) coarsened trabeculae
3) cortical thickening
4) bone enlargement
5) subarticular location
6) pathologic fx
7) pseudo fx
8) bowing deformities
9) sharp lytic area w/short zone of transition
--osteoporosis circumscripta in skull
T/F Paget's always begins at one end of a bone in the subarticular region, and progresses towards other end.
Paget's in the skull you see?
-map like resorption of bone
-inner table is not involved, but outter table of skull is resorbed from within (thicker)
-sutures are destroyed
What are the stages of Paget's in the skull?
1) Osteoporosis Circumscripta
2) Cotton Wool appearance = fuzzy, poorly defined margin of sclerotic areas
--irregular patches of bone in thickened diploe
--M/C stage
Paget's in the spine you see?
-Usu see stage 2 but stage 3(ivory vertebra) also seen
-Enlarged vertebra w/Rim of thickened cortex = Picture Frame appearance
-Accentuated Vertical Trabeculae
Paget's in the pelvis you see?
-commonly affected and usually seen in stage 2
-cortical thickening
-pubis and ischium expansion
-patchy sclerosis
-intermittent lucent defects
-increased trabeculae
-Rim/Brim Sign
-Protrusio Acetabuli
What is the Rim/Brim sign seen in the pelvis of Paget's?
Cortical thickening of the pelvic brim w/obliteration of Kohler's teardrop
Paget's in the femur you see?
-usu seen in stage 2
-begins as subarticular lesion and progresses toward other end
-ddx: FD begins in diametaphysis
-expanded corticies
-coarse trabecular patterns
-pseudo fx along covex side of subtrochanteric region of the femoral neck
-Shepherd's Crook deformity (varus deformity of hip)
Paget's in the tibia you see?
-Radiolucent defect beginning in subarticular end of proximal tibia extending down the shaft in a "candle flame/V-shaped" appearance("Blade of Grass")
--indicates advancing osteoclastic resorption
-Anterior bowing of tibia (Sabre Shin Deformity)
--extensive Paget's
What is used to ddx Paget's from Blastic/sclerotic metastasis?
-Bone Enlargement
-Squaring off of anterior vertebral body margins
-Endplate Thickening
-Occurs in subarticular end of bone
DDx osteolytic or osteoblastic metastatic carcinoma from Paget's.
-Lack of cortical thickening
-Frequent cortical disruption
-Lack of bone expansion (unless 1° thyroid or kidney carcinomoa)
DDx Hemangioma of bone from Paget's
-Vertical striations of hemangioma may resemble coarse vertical trabeculae of Paget's
-No endplate thickening