Focal ulcerative dermatitis ("breast buttons") in marketed turkeys.

Features of focal ulcerative dermatitis ("breast buttons"), a skin disease occurring most commonly in male turkeys, are described. Single or, less commonly, multiple ulcers 16 to >900 mm2 in size were located in the unfeathered breast skin over the anterior keel. Ulcer margins were raised, and the center was filled with a firmly adherent, hard scab. Microscopically, there was a sharp demarcation between the ulcer and adjacent hyperplastic epithelium. Vasculitis, necrosis of dermal vessels, mild to moderate heterophil infiltration, and fibrosis were found in the dermis. The characteristic granulomatous response to exudate seen in avian species was absent. Although bacterial colonies, foreign debris, and (rarely) fungi were found on the lesion surface, they were absent deep in the ulcer, suggesting they are not its cause. The lesion had no clinical effect on the turkey but was frequently trimmed at processing, resulting in downgrading and economic loss. There is no correlation between the size of "breast buttons" and occurrence of "breast blisters," an inflammation of the sternal bursa.