3.  Hamartomatous fibro-osseous metaplasia
 Age: 10-70; common in 2nd
- 3rd
decade
 Common locations:
◦ femur, tibia, pelvis, ribs, skull
 70% monostotic

4.  Radiography:
◦ Variable: fibrous matrix- ground glass osteoid matrix-
sclerotic
◦ Zone of transition narrow (sclerotic rim)

6. -Sclerotic lesion in femur
secondary to presence of
increased woven bone
-Pathologic fracture

8.  90% unilateral
 3% Albright’s Syndrome
◦ precocious puberty, café-au-lait spots, polyostotic bone
lesions
 Femur- Sheppard’s crook varus deformity
 Cherubism- expanding facial bones, sinuses
 Pregnancy- lesions may enlarge

9.  Monostotic: UBC
 Polyostotic: Ollier’s disease, mets
 Rib lesions: EG, Ewing’s, mets
 Skull base: meningioma- skull base hyperostosis,
Paget’s

10. -Differential Dx: UBC- FD may appear very
cystic on MR
-UBC cold on bone scan; FD- warm

12.  Occurs only in the tibia and fibula
 Infants and children
 X-ray: mixed lucent/sclerotic, thickened cortex
(anterolateral), anterior bowing, synchronous
tibia/fibula
 DDX: adamantinoma (epithelial nature)
◦ slightly older age >20

14.  Epiphyseal lesion
 Age: <30 (growth plate usually open)
 X-ray: epiphysis, lytic destructive lesion, centrally
located, usually extends into metaphysis,
 DDX: CIGG – chondroblastoma, infection, GCT,
intraosseous ganglion,
 DDX: EG, ABC, mets, myeloma

16. T1
T2
T1 GAD

18.  PF: S.T. mass with vascular calcifications
 MRI: T1:
◦ Lacy high signal within lesion represents fat within
lesion
◦ T2 and T1 post Gad: tortuous vascular channels
possible phleboliths
◦ Most common S.T. mass of childhood; intramuscular;
size may vary throughout the day

20.  Primary small cell bone neoplasm
 Derived from reticulocyte- occurs in areas of red
marrow; long bones, axial skeleton
 Diaphyseal- older; Metaphyseal younger
 Age: 1st
–2nd
decade; 96% Caucasian

21.  Radiography
◦ Highly aggressive tumor; permeative pattern
◦ Medullary tumor; infiltrative; periosteal reaction-
spiculated, lamellated- many layers present
◦ No mineralized matrix
◦ S.T. mass common
◦ DDX: EG, lymphoma, OS, infection

23.  Typically metastatic to bone; common tumor in
childhood
 In childhood- acute leukemia,
◦ lymphocytic or undifferentiated
 50% of children have osseous involvement at
time of DX, and 70-80% during disease

24.  Childhood radiographic changes
◦ Radiolucent metaphyseal bands- growth arrest
disturbance; not leukemic infiltrate- involve areas of rapid
growth
◦ Diffuse osteopenia- often the only finding
◦ Periosteal reaction- lamellated
◦ Osteolytic lesions- permeative/ moth eaten
◦ Sclerotic lesions

27.  One of the most common bone tumors
 Almost always in long bones (femur, tibia)
 Age: Usually > 2 y.o. and < 20 y.o.
 Histo: fibroblasts and giant cells
 Usually regress with age; rarely seen in 30’s
 Usually an incidental finding

28.  Radiography
◦ Unilateral or bilateral
◦ Osteolytic lesion; well defined; sclerotic margin; oval,
scalloped, lobulated, eccentric,
◦ Metadiaphyseal, cortically based,
◦ Periosteal reaction absent- unless path fracture
◦ Femur: posteromedial; healing begins in diaphyseal
region

31.  Jaffe-Campanacci Syndrome
◦ Multiple NOFs
◦ Café-au-lait spots
◦ Mental retardation
 precocious puberty, hypogonadism, cryptorchidism, ocular
anomalies, cardiovascular anamolies

34. T1
T2
T1 GAD

35.  Uncommon: long bones, spine, hands, feet,
pelvis, shoulder
 Age: 5- 20 y.o.
 Usually metaphyseal
 Highly vascular expansile lesion; multiple cavities-
filled with blood
 Primary or secondary lesion; solid component

36.  Radiography
◦ Expansile, geographic lytic lesion; eccentric
◦ Usually metaphyseal
◦ Margin- sharp, nonsclerotic; outer margin thinned, may
be imperceptible radiographically
◦ MRI/ CT fluid-fluid levels
◦ DDX: UBC, NOF, FD, Osteoblastoma- spine,
Telangiectatic osteosarcoma

41.  Long bones- (prox humerus/ femur) metaphyseal-
move toward diaphysis with bone growth
 Age: 1st
two decades of life
 Bone cyst- serosanguineous fluid
 Bony septations
 Pathologic fractures 2/3’s of cases

42.  Radiography
◦ Well-defined lytic lesion- central in medullary space;
bone expansion, sharp margin
◦ Periosteal reaction only in presence of path fracture-
“fallen fragment sign”
◦ Radiolucent with trabeculation
◦ DDX: FD, ABC, NOF

46.  Nonneoplastic lesion of bone
(reticulohistiocytosis)
 Usually solitary- EG
◦ Multiple- Hand-Schuller-Christian
◦ Systemic- Letterer-Siwe
◦ Long bones, skull, spine, ribs, pelvis
◦ Age: 1st
two decades (5 – 10 y.o.)

47.  Radiography
◦ Variable: osteolytic oval, slow growing lesion
occasionally aggressive appearing
◦ Medullary space; centrally located
◦ Periosteal reaction – 10% of cases
◦ Nucs scan – negative 1/3 of cases

50.  Metaphyseal- epiphyseal lesion; long bones
 Age: 20 - 50 y.o. (growth plate closed) rare under
age 15 y.o.
 Progressive potentially malignant lesion
 Histo: Giant cells and mononuclear spindle
shaped cells

51.  Radiography
◦ Lytic lesion; arises in metaphysis and extends into
epiphysis; growth plate closed
◦ Well defined, nonsclerotic margin, abuts articular
surface, eccentric, usually large (> 4-6cm)
◦ Radiographic appearance does not help in determining if
benign or malignant

54.  Exostosis; bony projection with a cap of hyaline
cartilage; aberrant cartilage
 Metaphyseal, points away from joint; long bones,
around knee
 Age: 2nd
decade; growth stops when growth plate
closes
 Single or multiple; sessile, pedunculated
 Malignant potential; increase with multiple lesions

55.  Radiography
◦ Bony projection; contiguous medullary space and cortex;
overlying cartilage cap
◦ Pedunculated/ sessile
◦ Pain- malignant transformation/ mechanical problems,
bursa formation
◦ Cartilage cap; normally < 1-2 cm

56.  DDX:
◦ Single lesion: Parosteal osteosarcoma (no continuity of
medullary space and cortex)
◦ Multiple: Enchondromatosis; FD
◦ Malignant Transformation: Chondrosarcoma;
 Pain; Growth after growth plate closes
 Cartilaginous cap > 2cm thick

59. T1
T2
T1 GAD

60.  Similar to osteoblastoma; < 2 cm in size
 Femur/ tibia/ bones of the hands/ feet/ spine
 Usually cortical;Fibrovascular nidus (< 1cm);
adjacent reactive bony sclerosis
 Night pain relieved by aspirin
 Age: < 25 y.o.

61.  Radiography
◦ Round/ oval radiolucency (nidus <1-2cm)
◦ Cortically located
◦ Thick adjacent bony sclerosis
 Nucs: “Target” sign; MR: Nidus- bright on T2
with marked enhancement with Gad; CT used
to identify the nidus
 DDX: stress fracture, osteomyelitis

63.  Malignant bone tumor that forms osteoid tissue
 Most common primary malignant bone tumor
other than multiple myeloma
 Involves areas of active growth; Metaphysis;
femur, humerus, tibia, pelvis
 Age: 2nd
decade

64.  Radiography
◦ Aggressive tumor; lytic (permeative)/ sclerotic
(amorphous, cloudlike)/ mixed
◦ Periosteal reaction: lamellated, spiculated
◦ Large S.T. mass; skip lesions (MRI)

65.  Subtypes
◦ Telangiectatic: (<20y.o.) Lytic, expansile, aggressive,
may mimic ABC radiographically
◦ Parosteal: (2nd
-5th
decades) low grade, better prognosis,
stuck on appearance post femur
◦ Periosteal: (20 y.o.) Surface OS, aggressive, better
prognosis than conventional OS; tibia
◦ Multicentric: synchronous lesions, poor prognosis;
sclerotic lesions; children

68.  Synovial metaplasia; multiple osseous/
cartilaginous intraarticular loose bodies
 Nourished by synovial fluid
 Limited ROM/ pain
 DDX: PVNS, loose bodies DJD
 Monoarticular; knee, hip, shoulder, elbow

69.  Radiography
◦ Effusion present; abnormal calcifications
◦ Ossified loose bodies seen on plain film
◦ Cartilaginous loose bodies seen on MR
◦ Secondary OA
◦ Pressure erosive changes