Bone Tumors Flashcards
Lucent Epiphyseal Lesions
AIG“the evil” Company
- ABC
- Infection
- Giant cell
- Chondroblastoma
What bones are epiphyseal equivalents?
- Carpals
- Patella
- Greater Trochanter
- Calcaneus
Differential diagnosis for lucent bone tumors in patients that are:
- Less than 30
- Any age
- Over 40
Less than 30 = EG, ABC, NOF, Chondroblastoma, and Solitary Bone Cyst
Any age = Infection
Greater than 40 = mets and myeloma
Classic appearnce of Fibrous Dysplasia
Long lesion in a long bone with a ground glass matrix
No periosteal reaction or pain
What is the difference between McCune Albright and Mazabraud Syndrome?
Both are polyostotic fibrous dysplasia syndromes
McCune Albright
- Girl
- Cafe au lait spots
- Precocious puberty
Mazabraud
- Woman (middle aged)
- Soft tissue myxomas
- Increased risk for osseous malignant transformation
What is Jaffe-Campanacci Syndrome?
***Low yield
- NOFs
- Cafe au lait spots
- Mental retardation
- Hypogonadism
- Cardiac malformations
How do you differentiate an enchondroma from a low grade chondrosarcoma?
Pain: Low grade chondrosarcomas can be painful
Size: Enchondroma (1-2 cm) vs low grade chondrosarcoma (>4-5cm)
Changes: Archs and ring pattern may move around with low grade chondrosarcoma but will not change with an enchondroma
Name two multiple enchondroma syndromes
Ollier and Maffuci
Maffuci has More - Cancer risk and vascular malformations
If you see phleboliths or hemangiomas (lucent centered calcifications) think Maffuci
3 classic Eosinophilic Granuloma (EG) appearances
- Vertebral plana in a kid
- Skull with lucent beveled edge (also in a kid)
- “Floating Tooth” with lytic lesion in alveolar ridge – differential case
Classic DDx for Osseous Sequestrum
- Osteomylitis
- Lymphoma
- Fibrosarcoma
- EG
*Osteoid Osteoma can mimic a sequestrum
Classic DDx for vertebra plana
MELT
- Mets / Myeloma
- EG
- Lymphoma
- Trauma / TB
Facts about Giant Cell Tumor (GTC)
- Physis must be closed
- Non sclerotic border
- Abuts the articular suface
Things to know
- Most common in the knee - abuting articular surface
- Most common at age 20-30
- Association with ABCs (can turn into them)
- They are “quasi-malignant” - 5% can mets to the lung
- Fluid levels on MRI

What is typical apperance of an osteoid osteoma?
Oval lytic lesion (“lucent nidus”) surrounded by dense sclerotic bone

Classic DDx for lucent lesion in the posterior elements
- Osteoblastoma
- ABC
- TB
Typical age and location for a solitatry bone cyst
Less than 30 years old
Proximal humerus > femur > calcaneus
Fallen fragment sign = bone fragment in the dependent portion of a lucent bone lesion

Lytic or sclerotic lesion with history of hyperparathyroidsm think…
Brown tumor
Classic blastic mets are
Prostate, carcinoid, and medulloblastoma
Classic lytic mets are
Renal and Thyroid
Test to differentiate a bone island from a prostate met
Bone scan
Bone Island should be mild or not active
Prostate met should be HOT
Multiple myeloma typically spares
Posterior elements
Multiple myeloma can manifest as
Diffuse osteopenia
Classics: Long lesion in a long bone
Fibrous dysplasia
Classics: Ground glass
Fibrous dysplasia
Classics: Lytic lesion with a hazy matrix
Fibrous dysplasia
Classics: Chondroid matrix in the proximal humerus or distal femur
Enchondroma
Classics: Lucent lesion in the finger or toes
Enchondroma
Classics: Epiphyseal tibial lesion in a teenager
Chondroblastoma
Classics: Epiphyseal equivalent lesion
Chondroblastoma or GCT
*Technically GCT grows into the epiphysis
Classics: Lucent lesion with a fracture (fallen fragment) in the humerus
Solitary (Unicameral) bone cyst
Classics: Lucent lesion in the greater trochanter
Chondroblastoma
Classics: Calcaneal lesion with a central calcification
Intraosseus lipoma
Classics: Lucent lesion in the skull
EG
Classics: Vertebra planna in a kid
EG
Classics: Vertebra plana in an adult
Mets (or myeloma)
Classics: Sequestrum / nidus in the tibia or femur
Osteoid osteoma
Classics: “Painful Scoliosis”
Osteoid osteoma
Classics: Calcified lesion in the posterior elements of the C-Spine
Osteoblastoma
Malignant Fibrous Histocyoma (aka Pleomorphic Undifferentiated Sarcoma)
- Old people and central location (proximal arms and legs)
- Dark to intermediate on T2
- Assocated with spontanous hemmorhage
- Bone infarcts can turn into MFH
- Radiation is a risk factor
Synovial sarcoma
- Young
- Peripheral (knee, foot)
- T2 triple sign (bowl of grapes)
Random trivia
- Most sarcomas don’t attack bones; synovial sarcoma can
- Most sarcomas present as a painless mass; synovial sarcomas can hurt
- Soft tissue calcifications and bone erosions are highly suggestive
- Slow growing and small in size can trick people into thinking it is B9

Myxiod Liposarcoma
- Most common liposarcoma in patients younger than 20
- Can look like a cyst (T2 bright and T1 dark) - confusing
- Need gad to differentiate
Soft tissue myxoma signal characteristics
- T2 bright
- T1 iso to dark
Multple soft tissue myxomas + polyostotic fibrous dysplasia = Mazabraud Syndrome
Treatment Trivia
Osteosarcoma
Chemo first (to kill micro mets) followed by wide excision
Treatment Trivia
Ewings
Both chemo and radiation followed by wide excision
Treatment Trivia
Chondrosarcoma
Usually wide excision (low grade and major concern is local recurrence)
Treatment Trivia
Giant Cell Tumor
Because it extends to the articular surface it will require arthroplasty
PVNS versus Synovial Chondromatosis
- PVNS is associated with hemarthrosis (blooming on GRE)
- PVNS never calcifies
- Synovial chondromatosis may calcify (see on plainfilm below)

Lipoma arborescens appearance
- “Frond like”
- Behaves like fat (T1 bright, T2 bright, response to fat saturation)
- Associated with OA, chronic RA, or prior trauma
Tricks:
- Shown on gradient and need to appreciate fat-fluid interface
- Shown on US with “frond-like hyperechoic mass”

Cortical Desmoid
- DO NOT TOUCH LESION
- Location = posteriomedial epicondyle of the distal femur
- Tug lesion
- Can be hot on bone scan

Synovial Herniation Pit / Pitt’s Pit
- Characteristic location in the anterosuperior femoral neck
- Lytic appearing lesions
- Associated with femoral acetabular syndrome?
DO NOT TOUCH LESION