Telangiectatic osteosarcoma in four dogs: Cytologic, histopathologic, cytochemical, and immunohistochemical findings

Vet Clin Pathol. 2024 Mar;53(1):85-92. doi: 10.1111/vcp.13338. Epub 2024 Feb 28.


Telangiectatic osteosarcoma is a rare variant of osteosarcoma histologically and clinically similar to hemangiosarcoma (HSA). This case series describes the imaging and cytologic features of four histologically confirmed telangiectatic osteosarcomas, including the use of cytochemical stains. Alkaline phosphatase (ALP) was applied to Wright-Giemsa-stained cytology slides, and Factor VIII immunohistochemistry was evaluated. Cytologic characteristics included atypical mesenchymal cells with evidence of acute and chronic hemorrhage. Telangiectatic osteosarcoma cases had positive ALP cytochemical staining, while control HSA cases were negative. Factor VIII immunohistochemistry was negative in telangiectatic osteosarcoma and positive in HSA. Cytologic diagnosis of telangiectatic osteosarcoma with positive ALP cytochemical staining can help differentiate this neoplasm from HSA.

Keywords: alkaline phosphatase; bone neoplasm; factor VIII immunohistochemistry; hemangiosarcoma.

Publication types

  • Case Reports

MeSH terms

  • Animals
  • Bone Neoplasms* / diagnosis
  • Bone Neoplasms* / veterinary
  • Coloring Agents
  • Dog Diseases* / diagnosis
  • Dogs
  • Factor VIII
  • Hemangiosarcoma* / pathology
  • Hemangiosarcoma* / veterinary
  • Osteosarcoma* / diagnosis
  • Osteosarcoma* / veterinary


  • Factor VIII
  • Coloring Agents