Pediatric Bone Tumors

Fibrous Dysplasia

  • Hamartomatous fibro-osseous metaplasia
  • Age: 10-70; common in 2nd – 3rd decade
  • Common locations: femur, tibia, pelvis, ribs, skull
  • 70% monostotic
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  • Radiography
    • Variable: fibrous matrix- ground glass osteoid matrix- sclerotic
    • Zone of transition narrow (sclerotic rim)
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-Sclerotic lesion in femur secondary to presence of increased woven bone

-Pathologic fracture

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  • Monostotic: UBC
  • Polyostotic: Ollier’s disease, mets
  • Rib lesions: EG, Ewing’s, mets
  • Skull base: meningioma- skull base hyperostosis, Paget’s
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-Differential Dx: UBC- FD may appear very cystic on MR

-UBC cold on bone scan; FD- warm

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Polyostotic Fibrous Dysplasia

  • 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

Osteofibrous Dysplasia

  • 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
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Chondroblastoma

  • Epiphyseal lesion
  • Age: lt;(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
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Soft Tissue Hemangioma

  • 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
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Ewing's Sarcoma

  • 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
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Leukemia

  • 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
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Nonossifying fibroma

  • 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
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Jaffe-Campanacci Syndrome

  • Multiple NOFs
  • Café-au-lait spots
  • Mental retardation
  • precocious puberty, hypogonadism, cryptorchidism, ocular anomalies, cardiovascular anamolies
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Aneurysmal Bone Cyst

    • Uncommon: long bones, spine, hands, feet, pelvis, shoulder
    • Age: 5- 20 y.o.

Usually metaphysealHighly 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
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Unicameral Bone Cyst

  • 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
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Eosinophilic Granuloma

  • 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
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Giant Cell Tumor

  • Metaphyseal- epiphyseal lesion; long bones
  • Age: 20 – 50 y.o. (growth plate closed) rare under age 15 yr
  • 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
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Osteochondroma

  • 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
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Osteoid Osteoma

    • 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
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Osteogenic Sarcoma

  • 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
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Synovial Chondromatosis

  • 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