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What would be a differential for a bubbly lytic lesion of bone that is only seen in patients younger than 30?
- Unicameral Bone Cyst
- Aneurysmal Bone Cyst
What is a benign lytic bone lesion which lacks periosteal reaction?
What is a feature of Fibrous dysplasia which can help distinguish this process from a malignant process?
Fibrous dysplasia lacks a periosteal reaction.
What disease process can be excluded if there is periostitis associated with a lytic bone lesion?
Fibrous dysplasia can be excluded because it lacks a periosteal reaction.
What are some features of Fibrous Dysplasia
- Mono- or Polyostotic
- No periosteal reaction
- Painless, unless fractured
- Predilection for pelvis, prox femur, ribs, and skull. If it is in the pelvis, then it is also usually in the ipsilateral prox femur.
- Ground-glass or smoky appearance but can be entirely lytic.
What is the radiographic progression of fibrous dysplasia?
- Lytic initially
- Ground-glass or smoky when the lesion begins to calcify
- Sclerotic when significantly calcified later.
What does fibrous dysplasia look like in the ribs?
Lytic and expansile in the posterior ribs.
Sclerotic in the anterior ribs.
What are components of McCune-Albright?
- Polyostotic fibrous dysplasia
- Cafe-au-lait spots
- Precocious puberty
What is cherubism? prognosis?
Multiple fibrous dysplasia lesions of the jaw giving child with puffed cheek look.
The lesions will regress in adulthood.
Remember... with FD there should be no periosteal reaction.
What is the MC B9 cystic lesion of the phalanges?
What does it look like?
Lytic lesion, most commonly presenting with pathologic fracture.
The phalanges are the only bone in the body where an enchondroma does NOT contain calcified chondroid matrix.
What is the two diseases with multiple enchondromas? What are distinguishing features?
- Ollier's disease and Mafucci syndrome.
- Ollier's is NON-hereditary and has NO malig potential.
- Maffucci Syndrome is NON-hereditary but HAS malignant potential.
- Maffucci syndrome is also assoc with multiple soft tissue hemangiomas which may contain phleboliths.
There is no periostitis or pain assoc with these enchondromas and will have calcification
Names for EG
- Histiocytosis X
- Betterer-Siwe disease
- Hand-Schuller-Christian disease
What does EG look like radiographically? How can it be distinguished?
- Almost exclusively in patients <30yo.
- Most are <20yo.
- It is also usually monostotic.
- It can also have an assoc soft tissue mass.
What is the DDx for a bone lesion with a sequestrum?
What % of Giant Cell tumors are malignant?
15% are malignant.
What are the Dx criterion for a Giant Cell Tumor?
- 1. Occurs only in patients with closed epiphyses
- 2. Must be epiphyseal and abut the articular surface
- 3. Eccentrically located
- 4. Non-sclerotic sharply defined zone of transition (this rule does not apply for flat bones, such as the pelvis and calcaneous)*-
What is a synonym for an NOF?
Fibrous cortical defect.
Some distinguish these based on size with FCD being <2cm and NOF being >2cm.
Where are NOFs usually located? classic appearance?
- metaphysis of long bones.
- scalloped and slightly expansile lesion arising from the cortex with a thin sclerotic border.
On cross-sectional imaging the cortex may be disrupted but this is cortical replacement by benign fibrous tissue and not an aggressive lesion.
What is necessary to dx NOF?
- Must be asymptomatic
- Must have no periostitis, unless h/o trauma
- Must be <30yo.
- Must be cortically-based.
Where are NOFs typically found (which bones)?
MC around the knee, but can be anywhere.
What is the DDx for an expansile lytic lesion of the posterior elements of the spine?
- Osteoblastoma (50% have speckled calcifications)
Where do osteoblastomas often occur? What do they look like?
- Often occur in posterior elements of the spine. 50% will have speckled calcifications.
- They simulate ABCs and giant osteoid osteomas.
- When ever including osteoblastoma in a DDx, also include ABC.
What should be included in DDx for ANY lytic lesion (benign or aggressive) in a person over 40?
What is the correct term for a bubbly lytic bone lesion from myeloma?
MC presentation of myeloma? clinical?
MC presents as diffuse permeative process in the skeleton in a patient over 40. Can be solitary or multiple.
Plasmacytomas (correct term for myelomatous lesion) can preceed clinical or hematologic e/o myeloma by 3-5 yrs.
What are the MC lytic mets? What met is ALWAYS lytic?
MC lytic mets are thyroid and renal.
Renal mets are always lytic.
What is a common location for plasmacytoma? What is plasmacytoma?
Ilium is common location for plasmacytoma, which is a bone lesion from myeloma.
What is a typical presentation for a patient with an ABC? Where can they occur?
Pain is common presenting complaint for an Aneurysmal Bone Cyst (expansile lesion in a patient <30yo)
They can occur anywhere, but will often occur in the posterior elements of the spine.
What is the appearance of a Unicameral Bone Cyst?
Centrally-located well-defined often asymptomatic lytic lesion.
3/4 of these occur in the proximal humerus
Requirements for Dx of Unicameral Bone Cyst?
- Must be central in bone
- Must be <30yo
- No periostitis.
What are bone lesions from hyperparathyroidism called? what do they look like?
Brown tumors and they can look like anything (lytic to sclerotic).
What radiographic appearance is pathognomonic for hyperparathyroidism? Where is this MC seen?
- Subperiosteal bone resorption, MC involving the radial aspect of the middle phalanges,
- distal clavicle,
- medial aspect of proximal tibia and
- sacroiliac joints.
If a bony sequestrum is present, what dx should be strongly considered?
- Others: FOLE...
What is DDx for lytic lesion in the epiphysis of a patient <30yo?
- 1. Infection (MC)
- 2. Chondroblastoma
- 3. Giant cell tumor
subchondral cysts or geodes can be seen with what disease processes?
- Rheumatoid arthritis
- CPPD (pseudogout)
- Avascular necrosis
DDx for rib lesions?
- Fibrous dysplasia
DDx for multiple bone lesions?
- Fibrous dysplasia
- Hyperparathyroidism (brown tumors)
What are 4 standard things to look at for a bone lesion to determine benign vs malignant? Which is most accurate?
- 1. Cortical destruction
- 2. Periostitis
- 3. Orientation of the lesion (not helpful)
- 4. Zone of transition
Zone of transition is most accurate.
What are aggressive patterns of periosteal reaction?
What are benign patterns?
What is a narrow vs wide zone of transition?
Narrow can be traced with a fine tip pencil.
Wide is mostly imperceptible
Malignant bone tumors in 1-30yo patient population?
- Ewing sarcoma
- Osteogenic sarcoma
Malignant bone tumors in 30-40yo patient population?
- Giant cell tumor
- Parosteal sarcoma
- Malignant fibrous histiocytoma
- Primary Lymphoma of bone
Malignant bone tumors in 40+yo patient population?
What are MR signal characteristics of most tumors? What are some exceptions to this and what are their MR signal characteristics?
Most tumors are Low T1, High T2.
- These exceptions are low T1 and low T2:
- Malignant fibrous histiocytomas
- Desmoid tumors
- Any tumor with calcifications
What is characteristic radiographic appearance of an osteosarcoma?
Osteosarcomas characteristically have a mixed lytic and sclerotic appearance on radiographs.
What bone tumor characteristically has a mixed lytic and sclerotic appearance on radiographs?
Osteosarcoma characteristically has a mixed lytic and sclerotic appearance on radiographs.
Osteosarcoma can also be entirely sclerotic or entirely lytic, but less commonly.
What is the MC primary malignant bone tumor? Who gets them?
Osteosarcoma is MC and MC occurs in kids and young adults (<30yo).
What is a cortical desmoid tumor?
It is an avulsion injury that is benign but can appear malignant on imaging and histology. It can mimic a parosteal osteosarcoma, especially when occuring at the posterior distal femur, which is a common location for parosteal osteosarcomas.
Where does a parosteal osteosarcoma arise from? Where does it commonly occur?
Parosteal osteosarcoma arises from the periosteum and grows outside the bone, commonly circumferentially around the bone.
Parosteal osteosarcoma commonly arises from the posterior distal femur, by the knee.
Classic appearance of a Ewing Sarcoma?
permeative lesion in the diaphysis of a long bone in a child. Most often it will have onion-skin periostitis or sunburst periostitis.
What diagnosis should be considered in a patient >40yo with a bony or soft tissue mass with amorphous, popcorn-like, or snowflake calcifications? What should be done with it?
Chondrosarcoma should be considered and biopsy should be performed.
What is the radiographic appearance of a fibrosarcoma?
Lytic bone lesion (commonly moth-eaten) with a possible bony sequestrum (FOLE), and without reactive new bone formation in a patient in their 30s-40s.
Are Desmoid tumor and cortical desmoid synonymous?
No. Cortical desmoid tumor is benign avulsion injury.
Desmoid tumor is a half-grade fibrosarcoma. It MC arises in the soft tissues and is uncommon in the bony skeleton
What is another name for reticular cell sarcoma?
Primary lymphoma of the bone and has an appearance that can be identical to Ewing sarcoma, but occurs in an older population.
Think of this is the bone is widely involved but the patient is asymptomatic.
What is one of the only bone tumors that is not characteristically hot on bone scintigraphy?
A lytic bone lesion from myeloma is called a plasmacytoma.
What are the two MC soft tissue malignancies of the musculoskeletal system?
- Malignant fibrous histiocytoma
Multiple calcified loose bodies in a major joint (esp hip) are pathognomonic for what?
PVNS calcifications typically occur where?
- Trick question...
- PVNS virtually never has calcifications.
Hemangiomas often cause cortical holes in adjacent bone that can mimic a permeative (moth-eaten) pattern. T or F?
What is the MC arthritide? What are the hallmarks of it?
Osteoarthritis or DJD is MC.
- joint space narrowing
What are the two types of osteoarthritis? How are they distinguished?
Secondary & Primary.
Secondary is what is commonly discussed when talking about DJD and is MC secondary to trauma.
- Primary is a familial arthritis that MC occurs almost exclusively in middle-aged women and ONLY in the hands, affecting the DIP, PIP, and 1st CMC bilaterally and symmetrically.
- Primary can be very painful and debilitating and can become "erosive osteoarthritis."
Erosions of the TMJ, AC joint, SI joint, and/or pubic symphysis should make you consider what disease?
Extensive osteophytosis of the spine without significant disk space narrowing or sclerosis is characteristic of ...
DISH (Diffuse Idiopathic Skeletal Hyperostosis).
What are geodes? What are they associated with?
- Geodes are cystic formations that occur periarticularly.
- They can be seen with DJD, Rheumatoid, CPPD, and avascular necrosis.
Hallmarks of Rheumatoid arthritis?
- Soft tissue swelling
- joint space narrowing
- marginal erosions
- prox distribution (hands)
- bilateral symmetry
What diseases should be considered with a high-riding humeral head?
- Rotator cuff tear
- Rheumatoid arthritis
What is the femoral head migration pattern with rheumatoid versus osteoarthritis?
- Axial migration = Rheumatoid
- Superior migration = Osteoarthritis
What diseases are considered when discussing HLA-B27 spondyloarthropathies? They are characterized by what features?
- ankylosing spondylitis
- inflammatory bowel dz
- psoriatic arthritis
- Reiter syndrome (aka reactive arthritis)
- Characterized by bony ankylosis,
- proliferative formation of new bone
- predominantly spine involvement
- syndesmophyte formation (vertically oriented)
What diseases have symetric bilateral syndesmophytes?
- Ankylosing spondylitis
- Inflammatory Bowel Dz
What diseases have asymmetric unilateral syndesmophytes?
- Psoriatic arthritis
- Reiter syndrome
What diseases cause bilaterally symmetric SI joint disease which is initially erosive then progresses to sclerosis and fusion?
- Ankylosing spondylitis
- Inflammatory bowel disease
Reiter syndrome and psoriatic arthritis can be either unilateral or bilateral in the SI joint.
DDx for bilaterally symmetric SI joint disease
- Ank spon
- Psoriatic arthritis
- Reiter syndrome
Bamboo spine is classic for ...
Other than the spine, what other joint is commonly involved in ankylosing spondylitis? How often?
The hip is also involved in apx 50% of ankylosing spondylitis cases.
Other than Gout, what disease commonly affects the IP joint of the great toe?
Reiter disease commonly affects the IP joint of the great toe.
What are the crystal-induced arthritides?
- Ochronosis (rare)
- Wilson disease (rare)
Why is gouty arthritis not commonly seen? What are the radiographic features of gouty arthritis?
It is not commonly seen because it takes 4-6 yrs to develop radiographically evident change. These patients are usually treated before progression to this level.
- Hallmarks of Gout
- Well-defined erosions with sclerotic margins
- soft tissue nodules
- random distribution
- no osteoporosis
What is the association between Gout and pseudogout? How is this seen radiographically?
Apx 40% of patients with gout also have pseudogout (CPPD) which is radiographically apparent as chondrocalcinosis.
What can be used as a distinguishing feature for gout?
The sclerotic margins of the erosions of gout are rarely seen with any other arthritides.
What is the classic triad of Pseudogout?
- cartilage calcification
- joint destruction
What are the MC locations of CPPD deposition?
- The MC locations of pseudogout are...
- Pubic symphysis
Chondrocalcinosis of the knee, TFCC, or pubic symphysis is virtually diagnostic of what condition?
Virtually all chondrocalcinosis is secondary to ...
calcium pyrophosphate deposition into the articular cartilage
DJD secondary to CPPD is MC involving which joints?
- radiocarpal joint
- patellofemoral joint
- metacarpophalangeal joints
Degenerative changes of these joints are MC due to CPPD.
What test can confirm CPPD in an affected joint?
Joint aspiration looking for CPPD crystals
What are three diseases with a high association with CPPD?
- primary hyperparathyroidism
These diseases commonly occur simultaneously with pseudogout.
Severe ulnar deviation of the phalanges is characteristic of ...
What collagen vascular diseases will commonly have hand arthritis?
- Mixed connective tissue disease
They are all assoc with muscle wasting of the hands and osteoporosis. There are no erosions, typically.
What diseases should you think of if you see soft tissue calcifications? How do you distinguish these?
Scleroderma - subcutaneous calcs
Dermatomyositis - intramuscular calcs
Lytic destructive lesions in the cortex of the hand bones which has a "lace-like" appearance should make you consider...
What % of patients with hemochromatosis will have hand arthropathy? What does it look like?
20-50% of hemochromatosis patients will have hand findings consistent with DJD of the 2nd - 4th MCP joints.
50% also have CPPD.
Another finding with Hemachromatosis is squaring of the metacarpal heads secondary to large osteophyte formation which have a drooping appearance.
Destruction, dislocation, and heterotopic new bone is the classic triad for what disease process? Where is MC seen?
MC seen in the 1st & 2nd TMT joints in a diabetic foot.
Epiphyseal enlargement with gracile (thin) diaphysis is classic for what diseases?
JRA & hemophilia
What is a Charcot spine?
Severe joint destruction of the spine with malalignment/dislocation in a paralyzed patient.
What joints are MC involved with osteochondromatosis? Is it always radiographically apparent?
knee, hip, and elbow
30% of the time the cartilaginous deposits don't calcify and the only thing radiographically apparent is either joint effusion or joint destructive changes.
What treatment is often necessary for synovial osteochondromatosis?
What processes should be considered if erosions of the femoral head give the femoral neck an apple core appearance and there are no calcifications?
- Synovial chondromatosis
What is "Tumefactive synovial chondromatosis?"
Loose bodies tightly packed in a joint, giving it an appearance of a solid tumor. NO MALIGNANT TUMORS ARISE IN JOINTS.
What should ALWAYS be added to DDx when considering PVNS?
Synovial chondromatosis. They are indistinguishable radiographically.
MR signal characteristics of PVNS are due to what? What are the MR characteristics?
Low T1 and T2 signal is due to hemosiderin lining the synovium.
A patient has a h/o minor trauma to an extremity. They subsequently present with pain, swelling, and dysfunction. Radiograph shows severe patchy aggressive osteoporosis (may only be periarticular) and soft tissue swelling. What disease should be considered (3 names for this dx). Why is it important to notify the provider?
- Sudeck Atrophy
- aka reflex sympathetic dystrophy
- aka shoulder-hand syndrome
MC affects the hand or foot.
So that aggressive physical therapy can be started.
What should be done next for a patient with hip pain and a joint effusion?
Joint aspiration to r/o infection.
How is a knee effusion determined? What are the two fat pads separated by a knee effusion?
If the suprapatellar fat-pad and the anterior femoral fat-pad are separated by >10mm, then this is consistent with a knee effusion. <5mm is considered a normal measurement.
What are causes of AVN of bone?
- Cason's Dz
What is the hallmark of AVN?
Increased bone density at an otherwise nml joint.
What is the earliest sign of AVN? What comes next?
- then patchy or mottled bone density
- then subchondral lucency
- then collapse of the articular surface and joint fragmentation
- These changes only occur on one side of the joint. Most other joint processes occur on both sides.
What is a distinguishing feature of AVN?
It only occurs on one side of the joint. Most other joint processes involve both articular surfaces.
What is the most sensitive study available for the evaluation of AVN?
AVN of the lunate?
AVN of the tarsal navicular?
AVN of the metatarsal head?
AVN of the femoral head?
AVN of the ring epiphyses of the spine?
AVN of the tibial tubercle?
What does AVN look like on MR
Low T1 signal of the involved area.
What is secondary osteoporosis?
- Osteoporosis secondary to underlying disease, primarily thyrotoxicosis or renal disease.
- 5% of osteoporosis is of the secondary type.
What is the main radiographic finding of osteoporosis?
Thinning of the cortex.
DDx for permeative pattern of bone?
- Ewing sarcoma, infection, EG.
- Older patient:
- Mets, myeloma, lymphoma
- aggressive osteoporosis, hemangioma, or radiation changes if actually pseudopermeative.
What is osteomalacia? What is the MC cause?
Osteomalacia is due to too much non-mineralized bone. The MC cause is renal osteodystrophy.