Hamartomatous fibro-osseous metaplasia Age: 10-70; common in 2nd - 3rd decade Common locations:
◦ femur, tibia, pelvis, ribs, skull 70% monostotic
Radiography:◦ Variable: fibrous matrix- ground glass osteoid
matrix- sclerotic◦ Zone of transition narrow (sclerotic rim)
-Sclerotic lesion in femur secondary to presence of increased woven bone
-Pathologic fracture
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
Monostotic: UBC Polyostotic: Ollier’s disease, mets Rib lesions: EG, Ewing’s, mets Skull base: meningioma- skull base
hyperostosis, Paget’s
-Differential Dx: UBC- FD may appear very cystic on MR
-UBC cold on bone scan; FD- warm
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
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
T1
T2
T1 GAD
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
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
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
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
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
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
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
Jaffe-Campanacci Syndrome◦ Multiple NOFs◦ Café-au-lait spots◦ Mental retardation
precocious puberty, hypogonadism, cryptorchidism, ocular anomalies, cardiovascular anamolies
T1
T2
T1 GAD
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
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
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
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
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.)
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
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
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
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
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
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
T1
T2
T1 GAD
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.
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
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
Radiography◦ Aggressive tumor; lytic (permeative)/ sclerotic
(amorphous, cloudlike)/ mixed◦ Periosteal reaction: lamellated, spiculated◦ Large S.T. mass; skip lesions (MRI)
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
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
Radiography◦ Effusion present; abnormal calcifications◦ Ossified loose bodies seen on plain film◦ Cartilaginous loose bodies seen on MR ◦ Secondary OA◦ Pressure erosive changes