ISSN 2398-2969      

Bone: neoplasia



  • 3-5% of all canine tumors.
  • Incidence rate of 27.2 dogs per 100,000, however this depends on breed and specific country population.
  • Cause: lameness, bony swelling.
  • Diagnosis: clinical signs, radiography, histopathology.
  • Treatment: surgery +/- chemotherapy.
  • Prognosis: good for benign lesions, guarded for malignant, however 90% of bone tumors are histologically malignant.
  • Most common tumor is osteosarcoma, however multilobular osteochondrosarcoma, chondrosarcoama, fibrosarcoma and hemangiosarcoma are reported.
  • Metastases from other tumors, especially carcinoma of the urinary tract and mammary carcinoma.
  • Metastases of appendicular osteosarcoma and rib osteosarcoma are very common. Axial osteosarcoma carries a significant low metastatic rate compared to appendicular, but delayed metastases later than one year after diagnosis can occur. Axial osteosarcoma tend to be more locally aggressive and the control of the local disease is more difficult.





​​Local invasion

  • Other tumors invading bone locally, eg oral melanoma, SCC Skin: squamous cell carcinoma, fibrosarcoma.
  • In appendicular location, articular/periarticular histiocytic sarcoma Skin: histiocytoma can invade joint and bones. Rarely high grade subcutaneous STS Soft tissue sarcoma can invade the bone. Synovial cell sarcoma Synovial cell sarcoma can extend from the joint to invade bones.
  • See individual components for further information.


  • Etiology unknown, however micro-trauma/fractures in large breed dog could be potential contributing factors in a predisposed genetic background. Metal implants, osteomyelitis Osteomyelitis and fractures potential contributors of neoplastic transformations.
  • Malignant transformation of cells within bone (osteoblasts, chondroblasts, osteoclasts, etc)  →   uncontrolled proliferation and production of matrix (osteoid or chondroid).
  • Destruction of normal bone  →  lysis and possibly pathological fracture.
  • Metastasis common in appendicular and rib, less common in other axial locations.
  • Benign lesions are very rare and show less disorganization of normal bone structure. Bone cyst can appear clinically as a swelling, etiology is unclear.
  • Disruption of normal bone structure by cellular proliferation, matrix production and bone destruction causes periosteal reaction, pain and bony swellings.
  • Reduced weight bearing in limbs and therefore lameness.
  • Surrounding tissues are invaded to some extent but joint function is rarely compromised as invasion of the joint by osteosarcoma is rare.
  • Extreme bone lysis in long bones may lead to pathological fracture.
  • Mass affecting ribs may cause dyspnea or pleural effusion Pleural: effusion.
  • Mass affecting pelvis may cause constipation.
  • Mass in vertebral column may cause tetra/paraplegia.
  • Sites can be appendicular or axial skeleton.


  • Benign lesions progress slowly – months (benign lesions very rare).
  • Malignant lesions progress rapidly – days to months.
  • Osteosarcoma progress very rapidly - days to weeks.
  • Chondrosarcoma, fibrosarcoma and multilobular osteochondrosarcoma progress much more slowly than osteosarcoma.
  • Rarely low grade osteosarcoma (around 5% of cases) that can progress less rapidly is reported. Parosteal osteosarcoma is also slowly growing with lower metastatic rate.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Mason N J, Gnanandarajah J S, Engiles J B, Gray F, Laughlin D, Gaurnier-Hausser A, Wallecha A, Huebner M, Paterson Y (2016) Immunotherapy with a HER2-targeting listeria induces HER2-specific immunity and demonstrates potential therapeutic effects in a phase i trial in canine osteosarcoma. Clin Cancer Res 22, 4380-4390 PubMed.
  • Kruse M A, Holmes E S, Balko J A, Fernandez S, Brown D C, Goldschmidt M H (2012) Evaluation of clinical and histopathologic prognostic factors for survival in canine osteosarcoma of the extracranial flat and irregular bones. Vet Pathol 50, 704-708 PubMed.
  • Phillips B, Powers B E, Dernell W S, Straw R C, Khanna C, Hogge G S, Vail D M (2009) Use of single-agent carboplatin as adjuvant or neoadjuvant therapy in conjunction with amputation for appendicular osteosarcoma in dogs. J Am Anim Hosp Assoc 45, 33-38 PubMed.
  •  Liptak J M, Kamstock D A, Dernell W S et al (2008) Oncologic outcome after curative‐intent treatment in 39 dogs with primary chest wall tumors (1992–2005). Vet Surg 37, 488-496 PubMed.
  • Egenvall A, Nødtvedt A, von Euler H (2007) Bone tumors in a population of 400 000 insured Swedish dogs up to 10 y of age: incidence and survival. Can J Vet Res 71, 292–299 PubMed.
  • Boston S E, Ehrhart N P, Dernell W S, Lafferty M, Withrow S J (2006) Evaluation of survival time in dogs with stage III osteosarcoma that undergo treatment: 90 cases (1985–2004). JAVMA 228, 1905-1908 PubMed.
  • Barger A, Graca R, Bailey K, Messick J, De Lorimer L P, Fan T & Hoffman W (2005) Use of alkaline phosphatase staining to differentiate canine osteosarcoma from other vimentin-positive tumors. Vet Pathol 42, 161-165 PubMed
  • Baines S J, Lewis S, White R A S (2002) Primary thoracic wall tumours of mesenchymal origin in dogs: a retrospective study of 46 cases. Vet Rec 150, 335-339 PubMed.
  • Blackwood L (1999) Bone tumors in small animals. JSAP 21 (1), 31-37 VetMedResource.
  • Lascelles D & White D (1999) Principles of oncological surgery. In Practice 21 (4), 163-175 VetMedResource.

Other sources of information

  • Goldschmidt M H, Hendrick M J (2002) Tumors of the skin and soft tissues. In: Meuten D J (ed) Tumors in Domestic Animals. 4th edn. Ames, IA: Iowa State Press.

Further Information 

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