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Table of Contents
Definition / general | Prognostic factors | Treatment | Radiology description | Radiology images | Clinical images | Case reports | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Cytology images | Positive stains | Negative stains | Molecular / cytogenetics description | Electron microscopy description | Differential diagnosis | Additional referencesCite this page: Osteosarcoma-general. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/boneosteosarcomageneral.html. Accessed June 18th, 2018.
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
Images hosted on Pathout server:
Multifocal osteosarcoma
Blastic type, xray - contributed by Dr. Mark R. Wick
CT scan, cuboid bone - contributed by Dr. Mark R. Wick
Clinical images - contributed by Dr. Mark R. Wick
Clinical images
Images hosted on Pathout server:
Foot - contributed by Dr. Mark R. Wick
Case reports
- 15 year old boy with intracortical tumor of tibia (Am J Surg Pathol 1984;8:65)
- 21 year old man with metastases presenting as jejunal polyp (Arch Pathol Lab Med 2000;124:1682)
- 28 year old man with primary osteosarcoma of toe phalanx (Am J Surg Pathol 1988;12:300)
- 65 year old woman with fatal pulmonary embolism (Arch Pathol Lab Med 1999;123:437)
- 66 year old woman with a breast mass (Arch Pathol Lab Med 2003;127:e227)
- Patient with Cowden disease (Arch Pathol Lab Med 1993;117:1252)
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
Images hosted on Pathout server:
Hemorrhagic osteosarcoma
Distal femur - contributed by Dr. Mark R. Wick
Fibula - contributed by Dr. Mark R. Wick
Femur - contributed by Dr. Mark R. Wick
Images hosted on other servers:
Jejunal metastasis
Pulmonary embolus
Microscopic (histologic) 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
Microscopic (histologic) images
Images hosted on Pathout server:
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
Images hosted on other servers:
Osteoblastic
Chondroblastic
Quiz case
Osteolytic
Jejunal metastasis
Vascular invasion in jejunal metastasis
Cytology images
Images hosted on Pathout server:
FNAB - contributed by Dr. Mark R. Wick
Positive stains
- Alkaline phosphatase, vimentin, variable smooth muscle actin and desmin, S100 (if chondroid differentiation), vWF (Mod Pathol 2005;18:388), rarely hCG (Arch Pathol Lab Med 1989;113:416)
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
- Exuberant fracture callus
- Giant cell tumor: unlikely in metaphysis of young patient
- Myositis ossificans
Additional references
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