Rad 3 wk 7 (quiz 8)

Paget's disease aka

Osteitis deformans

AGE PN LOCATION for pagets

Age: over 50

Location: skull, femur, pelvis, spine (any osseous structure)

Pn: 90% asymptomatic

Pagets and fibrous dysplasia are both known as what

Great intimidators of bone disease

Pagets is a chronic metabolic bone disorder characterized by....

Excessive abnormal bone remodeling (disease of osteoclasts)

Paget's comes from what two things

Genetic or paroxysmal diseases

3 bone symptoms related to softening

1. Bowing

2. Tinnitus and hearing loss

3. Increase vascular output

Increased vascular output can lead to what and WHY

Heart failure

-highly vascular fibrovascular tissue infiltrates trabecular bone —> bone becomes super weak —> need a lot of blood to nourish it —> heart works too hard —> failure

____ hat size is common in pagets

Increasing

Which part of bone does pagets like

Subarticular location that usually extends into diaphysis

Explain mosaic appearance of Paget's disease

Patternless replacement of normal bone by pagetic vascular and fibrotic bone (page 489 for best example)

Initial treatment of pagets

Bisphosphatase

Complications of Paget's disease (10)

1. Shepard's crook

2. Saber shin deformity

3. Protrusio acetabuli

4. Basilar invagination, platybasia

5. Path fractures

6. Pseudo fractures

7. Spinal stenosis

8. Anemia

9. Paget coxopathy

10. High output cardiac failure (rare)

Shepherd's crook deformity

Deformity of proximal femur (coxa vara)

-seen in fibrous dysplasia too

Saber shin deformity

Anterior tibial bowing

Protrusion acetabuli

Acetabulum is weak so femur head pushes through

What line of mensuration is broken with protrusion acetabuli

Iliopectineal line

Basilar invagination and platybasia definitions and why do they happen

-Basilar invagination is when dens goes through foramen magnum

-Platybasiais when skull base enlarges

-Both happen because the weight of the skull causes flattening

Pathologic fractures of the ___ ___ and transverse banana like fracture of ___ bones is common

Vertebral body

Long bones

Pseudofracture def and which category of diseases do we see this in

Local areas of demineralization within the bone which are replaced by fibrous tissue (that's never mineralized —> weak)

-seen in bone softening diseases

Pseudofracture akas (4)

Loosers lines

Increment fractures

Milkman's syndrome

Umbau zonen

Paget's coxopathy definition and is most common where in skeleton

Represents articular cartilage destruction with secondary degen changes (cartilage becomes bone —> bone on bone)

-Hip (fem head and acetabulum)

High output cardiac failure is rare in Paget's, occurring when at least what fraction of skeleton is involved

1/3

How common is malignancy in pagets

Rare (1%)

What tells us that there is malignancy with Paget's

Symptoms of localized pain

Which malignant tumor do we see with pagets

Osteosarcoma

Where is osteosarcoma mc seen in pagets

Proximal femur

Lab findings for pagets

High hydroxyproline

High alkaline phosphatase

Normal calcium and phosphate

Why do we see high hydroxyproline in pagets

Due to Osteoclastic resorption, there is enhanced destruction of bone collagen, leading to increased in urinary excretion of hydroxyproline

Why is calcium and phosphorus levels normal in Paget's if its a Osteoclastic disease

Bone is responding to break down right away —> calcium taken up immediately as its being broken down

4 phases of pagets

1. Lytic (50%)

2. Combined/mixed (25%)

3. Blastic/sclerotic/ivory (25%)

4. Malignancy

Lytic phase of pagets we will see what on xray (2)

1. Osteoporosis circumscripta (ovoid lytic lysis in skull)

2. V sign/blade of grass (in lower extremity)

Mixed phase of pagets we will see what on xray (1)

Mosaic appearance

Blastic phase of pagets we will see what on xray (4)

1. Increased density/new bone

2. Cotton wool appearance of skull

3. Softening and enlargement

4. Basilar invag (sign of skull softening)

Is bone scan hot in pagets

Yes

Which imaging is best to see pagets and why?

Bone scan since theres high osteoblast activity and pagets is a polyostotic disease (seen in multiple locations)

Tom o'shanter sign

Enlargement of cranium (outer table growing out) combined with platybasia —> appearance of skull falling over facial bones

What 2 name signs do we see in spine for pagets and which phase do we see them in

1. Picture frame vertebra: thickened and enlarged vertebra endplate (sclerotic) creating squared off appearance. (Happens in mixed phase)

2. Ivory vertebra (happens in blastic stage?)

What rad changes do we see in pelvis

1. Cortical thickening and bone expansion

2. Thickening of iliopectineal line

3. Destruction of kohler's teardrop, known as pelvic rim/brim sign

What two name signs do we see in long bones

1. Saber shin appearance

2. Candle flame/v-shaped/blade of grass (lytic phase)

Candle flame appearance explained

Changes of radiolucent defect usually begin in the subarticular end of proximal tibia extending down the shaft

Does pagets cross skull sutures

Yes it dont gaf

Which table in the skull is destroyed in pagets

Outer table only (page 474)

How to ddx hemangioma from pagets in the spine if they both have trabecular accentuation

Pagets has cortical thickening/sclerosis, hemangiomas don't

Leontiasis ossea

Lion-like facial deformity seen in Paget disease due to facial bone involvement (RARE)

AGE PN LOCATION fibrous dysplasia

Age: 8-14

Location: ribs and fem (mono) / long bones, ribs, skull (poly)

Pain: not until path fx

Fibrous dysplasia represents a developments dysplasia due to ___ ____ resulting in overproduction of a cellular transmitter leading to defect in ___ ___

Genetic mutation

Osteoblastic differentiation

In FD, normal bone undergoes normal ____ and ___, but it's replaced with what

Resorption and remodeling

Replaced with differentiated osteoid/fibrous tissue with improper cell type differentiation

Improper cell type differentiation looks like what on xray for FD

Lytic + sclerotic (ground glass)

Improper cell type differentiation leads to what

Large fibrous stroma osseous lesions

What is McCune-Albright syndrome

Polyostotic FD + endocrine component

What is the endocrine component of McCune-Albright syndrome

Precocious (very early) puberty exclusively found in females

What deformities do we see in FD that we also see with pagets

Bowing deformities (shepards crook and saber shin)

What do we see on skin for FD

Cafe au lait spots (coast of Maine)

Why's FD cafe au lait spots called coast of Maine

Serrated irregular margin

Do we see cafe au lait spots for FD in the polyostotic or monoostotic type

Polyostotic

How to ddx cafe au lait spots with neurofibromatosis and FD (page 506)

Neurofibromatosis: coast of California (smooth)

FD: coast of Maine (serrated)

Which type of FD is more common? Mono or poly

Mono (75%)

Which type of FD has spinal involvement? And where in the vertebra is it mc

Poly, mc in vertebral body (spinal involvement in FD is rare though)

Cherubism

Familial FD of the mandible and maxilla

What do we see on xray for FD (4)

1. Widening of medullary canal, cortex thinning and endosteal scalloping

2. Ground glass appearance

3. Sarcomatous transformation (1% chance)

4. Radiolucent, loculated, well defined, maybe expansile

Most FD lesions demonstrate encapsulated sclerotic border around well defined lesion, what is this called

Rind of sclerosis

What other conditions other than FD do we see endosteal scalloping

Enchondroma and chondrosarcoma

Explain ground glass appearance

Fibrous based matrix with scattered bony spicules that renders an increase in radioopacity to existing radiolucent lesion (smoky/hazy)

-wipe out of trabecular patterns)

What malignant tumors are formed in the chance that FD develops malignancy (2)

Fibrosarcoma and osteosarcoma

FD Skeletal lesions are present at birth T/F

False, occur several years prior to puberty

FD is known to have ____ lesions in a ____ bone (femur)

Long, long

Expansile rib lesions for FD create what name sign

Extraplerual sign

What 3 conditions are MC for extrapleural sign

1. Blastic Mets

2. Fractures

3. Fibrous dysplasia

____ occurs as a FD complication of pathologic fracture and nonunion

Pseudoarthrosis (fake joint)

What're the two mc disorders of bone to produce pseudoarthrosis

Neurofibromatosis and FD