Abstract
A 13-year-old giraffe presented with dystocia. Previous history revealed she had given birth uneventfully to three calves and presented 2.5 years before with a pelvic mass and a history of trauma in the same location a few months before. Cytology and biopsies were nondiagnostic at that time. The mass grew for 2 years. Radiographically, the outer portion of the mass consisted of a thick, radiopaque capsule and irregular radiodensities within a radiolucent tissue. Deeper biopsies were obtained. Cytologically, they consisted of peripheral blood, round to oval, occasionally binucleate cells with an eccentric nucleus and moderate to abundant basophilic cytoplasm with small, clear vacuoles, accompanied by an eosinophilic granular background and a radiating basophilic or eosinophilic filamentous material. Histopathology revealed well-differentiated cartilage with mild to moderate anisokaryosis and anisocytosis of chondrocytes. A diagnosis of low-grade chondrosarcoma or chondroma was made. She was suspected to be pregnant, and treatment was postponed.
During dystocia, the fetus was manually positioned in a proper birth canal presentation, because one front limb and the head were flexed transversely and backward, respectively; it was pulled out, but it had died. Shortly thereafter, the dam fell down in shock with marked hypotension and died. Grossly, she had a 40-cm, white to blue-grayish, soft to gelatinous mass extending from the right ilium to the pelvic canal, with a thick bony capsule and multifocal mineralization and/or ossification. The rumen and abomasum were displaced to the right, and left and up, respectively; ruminal contents were watery. The calf had atelectasis of the right lung, but the left lung was expanded; the trachea and bronchi had yellowish fluid and froth. Microscopically, the tumor was a chondrosarcoma. The calf had amniotic fluid squames within airways and hepatocellular lipidosis. Dam’s death was attributed to possible amniotic fluid embolism, and contributing factors included ruminal fluid loss, retroperitoneal hemorrhage, exhaustion, stress, and compression of the thorax by abdominal viscera. To our knowledge, this is the first report of chondrosarcoma and of its etiologic role in dystocia in giraffes.2 Chondrosarcomas have predilection for flat bones.1
Literature Cited
1. McGavin, M.D., W.W. Carlton, and J.F. Zachary. 2001. Veterinary Special Pathology. Mosby Inc., St. Louis, MO.
2. Snyder, S.B., and M.J. Richard. 1997. Giraffe dystocia: a retrospective survey and four posterior presentation cases. Proc. Am. Assoc. Zoo Vet. Pp. 180–186.