Histopathology and epidemiology of condemnations due to squamous cell carcinoma in broiler chickens in North Carolina.

Squamous cell carcinoma (SCC) lesions were confirmed by histopathology in 94% of 176 carcasses condemned for SCC during 8-hour shifts at four different processing plants. Lesions in the remaining carcasses were diagnosed as focal ulcerative dermatitis. SCC lesions were confined to the skin; no metastasis or invasion of underlying muscle was present. Monthly prevalence of SCC condemnations at processing was obtained from two plants for a 1-year period and from two additional plants for 3-year periods. Overall study prevalence of SCC varied between 0.03% and 0.09% of total condemnations. Servicemen were found not to have an effect on SCC condemnations for the only company that had these data available. Chronological trends were evaluated for SCC condemnations. A trigonometric model predicted 6-month cycles for one processing plant over a 3-year period. The same model was used to describe 6-month cycles present in the last 12 months of a 3-year observation period in a different processing plant. Chronologic trends were evaluated qualitatively for the two other processing plants.