Bone
Osteosarcoma
Osteosarcoma-general

Author: Nat Pernick, M.D. (see Authors page)

Revised: 22 November 2016, last major update May 2014

Copyright: (c) 2003-2016, PathologyOutlines.com, Inc.

PubMed Search: Osteosarcoma
Cite this page: Osteosarcoma-general. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/boneosteosarcomageneral.html. Accessed December 2nd, 2016.
Definition / General
  • Most common primary bone tumor after myeloma
  • Definition: malignant bone tumor that produces osteoid directly from tumor cells and unconnected with cartilage, regardless of the amount of neoplastic cartilage or fibrous tissue present elsewhere
  • 60% male; usually ages 10 - 25 years or ages 40+ with other diseases (see below); rare before age 5
  • Associated with Paget disease after age 40 years (see below), post-radiation exposure (see below), Thorotrast administration, chemotherapy in children, fibrous dysplasia, osteochondromatosis, chondromatosis, rarely with hip implants
  • Not associated with trauma, although trauma may lead to discovery of tumor
  • Sites: metaphysis of long bones (distal femur, proximal tibia, proximal humerus; sites of peak mitotic activity for bone cells); occasionally diaphysis, rarely epiphysis; less common in flat bones or short bones; usually arises within medullary cavity and extends to cortex
  • Multicentric: usually children, densely sclerotic by Xray, extremely aggressive, associated with p53 mutations
  • Post-radiation: 10 - 15 years after 40 - 60 Gy exposure for various conditions; may cause fibrosarcoma, osteosarcoma or MFH; usually high grade, poor prognosis unless can excise with wide surgical margin
  • Codman's triangle: shadow between cortex and raised ends of periosteum (due to reactive bone formation), non specific
  • Biopsy: incision should be placed so it will be entirely removed by subsequent excision
  • Sites of metastasis: lung (98%, 20-80% at diagnosis, rarely within pulmonary arteries), other bones (37%), pleura (33%), heart (20%), rarely to lymph nodes, GI tract, liver, brain
  • Note: excision of metastatic lung nodules may prolong survival
Prognostic Factors
  • Poor: associated Paget disease, telangiectatic histology, elevated serum alkaline phosphatase, minimal postchemotherapy tumor necrosis, involvement of craniofacial bones (not jaw) or vertebrae, multifocal tumor, loss of heterozygosity of RB gene
  • Good: jaw or distal extremities; solitary; parosteal, periosteal or well differentiated intramedullary histology; extensive necrosis ( > 95%) after preoperative chemotherapy
  • 5 year survival: 70%
Treatment
  • Preoperative chemotherapy is helpful to spare limbs
  • MDR1 gene expression may determine chemosensitivity
Radiology Description
  • Large, destructive, lytic or blastic mass with permeative margins
  • May break through cortex and elevate periosteum
  • Sunburst pattern due to new bone formation in soft tissue
Radiology Images

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Multifocal osteosarcoma


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Blastic type, xray - contributed by Dr. Mark R. Wick

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CT scan, cuboid bone - contributed by Dr. Mark R. Wick

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Clinical images - contributed by Dr. Mark R. Wick

Clinical Images

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Foot - contributed by Dr. Mark R. Wick

Case Reports
Gross Description
  • Big, bulky, gritty, hemorrhagic with cystic degeneration
  • Spreads within medullary cavity, destroys cortical bone, elevates periosteum and invades soft tissue
  • Rarely penetrates joint along tendons / ligaments
  • May form satellite nodules (“skip metastases”)
  • Usually has well defined proximal and distal margins
  • 25% have large amounts of cartilage
Gross Images

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Hemorrhagic osteosarcoma

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Distal femur - contributed by Dr. Mark R. Wick

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Fibula - contributed by Dr. Mark R. Wick

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Femur - contributed by Dr. Mark R. Wick



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Jejunal metastasis

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Pulmonary embolus

Micro Description
  • High grade spindle cell tumor that produces osteoid matrix unconnected by cartilage (by definition)
  • Tumor cells produce neoplastic bone - basophilic thin trabeculae of neoplastic bone resembling fungal hyphae or neoplastic osteoid - eosinophilic, homogenous, glassy with irregular contours and osteoblastic rimming
  • Destroys or grows around trabeculae
  • Vascular invasion and necrosis common
  • May have osteoblastic, fibroblastic (pure spindle cell growth with minimal matrix) or chondroblastic predominance (malignant appearing cartilage with peripheral spindling and osteoid production)
  • Osteoid may be variable in amount
  • With bizarre giant cells in stroma or acellular stroma
  • Vessels may have hemangiopericytoma-like features
  • Tumor cells may be spindly, oval or round of variable size
  • 25% have osteoclast-like multinucleated giant cells
  • Cartilage may be mineralized, immature, myxoid
Micro Images

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Intracortical osteosarcoma

Foot osteoblastic - contributed by Dr. Mark R. Wick

Low grade sclerosing type - contributed by Dr. Mark R. Wick

Contributed by Dr. Mark R. Wick

Osteoblastic type with blue spiculated bone - contributed by Dr. Mark R. Wick

With infiltrative medullary growth - contributed by Dr. Mark R. Wick


Osteoblastic type - contributed by Dr. Mark R. Wick



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Osteoblastic

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Chondroblastic

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Quiz case

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Osteolytic

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Jejunal metastasis

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Vascular invasion in jejunal metastasis

Cytology Images

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FNAB - contributed by Dr. Mark R. Wick

Positive Stains
Negative Stains
Molecular / Cytogenetics Description
  • Usually aneuploid or hyperploid except periosteal and well differentiated (usually diploid), 20% have p53 mutations
Electron Microscopy Description
  • Differentiated tumor cells resemble normal osteoblasts with abundant dilated endoplasmic reticulum, rare mitochondria
  • Matrix composed of nonperiodic fibrils, scattered collagen fibers, focal calcium deposits of hydroxyapatite crystals
Differential Diagnosis
Additional References