Hemangiomas and hemangiosarcomas are benign or malignant vascular tumors which appear as masses in vascular spaces. Hemangiomas are one of the most common types of tumors associated with avian leukosis virus
subgroup J (ALV-J) in chickens.
- Hemangiomas: A benign tumor. Appears as raised, circular, blood-filled cystic masses (blood blisters). They obliterate pre-existent architecture, with adjacent channels separated only by a mature fibrous stroma without pericytes or smooth muscle.
- Hemangiosarcomas: These are malignant tumors. They appear similar to hemangiomas except these tumors have a more solid aspect, with local aggressiveness, infiltrative growth and it frequently produces distant metastases. They tend to cause inflammation and necrosis. These tumors are composed of pleomorphic hyperchromatic spindle cells that gain diagnostic specificity by at least the occasional formation of a convincing vascular channel supported by hyalinized collagen beams.
The most frequent locations where hemangiomas and hemangiosarcomas occur on chickens are the legs and feet, cloaca, neck, wings, and beak.
Hemangiomas and hemangiosarcomas can rupture easily, often leading to fatal blood loss.
Hemangiomas and hemangiosarcomas appear similar to malignant melanomas, hematomas, highly vascular granulation tissue, and vascular malformations such as arteriovenous fistulas and aneurysms.
Cutaneous hemangiomas can usually be successfully removed surgically.