Chapter 4 - Tumors

Several types of tumors besides those of the leukosis complex affect domestic poultry. Some of the more common ones include:

• Squamous cell carcinomas - skin tumors
• Adenocarcinomas - malignant tumors originating in glandular tissue and are common in older birds
• Leiomyomas - benign tumor of smooth muscle, usually in the uterus or digestive tract
• Fibromas - benign, usually enclosed tumors composed primarily of fibrous tissue and more common in older birds.
• Other - numerous other types of tumors occur in domestic poultry but at a low frequency

There is no evidence that any of these types of tumors are a health threat to humans. Carcasses with tumors are condemned only if there is ‘gross evidence’ of metastasis present. The general rule:

• One tumor → trim and pass inspection
• Two or more tumors → condemned if there is evidence of metastasis (the process by which a tumor spreads from the place at which it first arose)