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Hemangiomas are a benign neoplasm in cats that shows differentiation to vascular endothelium and the formation of blood vessels.

Gross Appearance

  • Those in the superficial dermis are usually elevated and blue to purple and the overlying epidermis may be ulcerated and bleeding
  • Those in the deep dermis and subcutis are usually larger with no abnormalities of the overlying skin
  • Dark red
  • Well demarcated
  • Encapsulated


  • Plump endothelial cells line vascular channels
  • Small or inconspicuous vascular lumina
  • Little nuclear atypia
  • Few mitotic figures


  • Lumina are large
  • Lumina are filled with erythrocytes and plasma
  • Vascular channels are lined by flattened endothelial cells
  • Neoplastic endothelium is supported by a fibrous stroma
  • Occasionally lumina are filled with thrombi