Case report 805: Synovial sarcoma, epithelial hyperplasia in the humeral air sacs, and formation of medullary bone.

In summary, we have reported a most interesting case of synovial sarcoma, epithelial hyperplasia in the air sacs, and formation of medullary bone in the left humerus of a 5-year-old female white pigeon. The tumor showed aggressive features radiologically and caused dysfunction of the left wing. The histologic findings and immunohistochemical reactions in this report were identical in many respects to the manifestation of synovial sarcoma described in human beings and dogs. Formation of medullary bone in female birds during the reproductive phase and hyperplasia of epithelia in the air sacs were also discussed.