Dorlis C. DVM, GPcertSAS, MRCVS, Resident of European College of Veterinary Surgeons, University of Edinburgh, Hospital for Small Animals, Roslin, Midlothian EH25 9RG | Pratschke K. MVB MVM MScClinOnc CertSAS DiplECVS FRCVS, Senior Lecturer, Small Animal Soft Tissue Surgery, University of Edinburgh, Hospital for Small Animals, Roslin, Midlothian EH25 9RG
Introduction
Extra-skeletal visceral osteosarcoma is a rare mesenchymal tumour arising from viscera and is characterized by osteoid formation in the absence of bone or periosteal involvement. There are few reports in the literature with extra-skeletal osteosarcoma associated with retained surgical sponges.
Materials and methods
A 5-year-old female neutered crossbreed dog presented with a history of acute vomiting. On physical examination, a mass was palpated in the middle portion of the abdomen. Computed tomography revealed a cavitated cystic mass originating from the mesentery. The dog underwent an exploratory abdominal surgery, and the mass was excised along with an associated part of the jejunum. Histopathology was consistent with extra-skeletal osteosarcoma. Fragments of refractile foreign material (possible gossypiboma) were present within the mass.
Results
The dog recovered from anaesthesia but was euthanized 3 days later after developing septic peritonitis due to the poor prognosis.
Conclusions
Extra-skeletal visceral osteosarcoma is a highly malignant tumour and rarely can be associated with retained foreign material in the abdominal cavity. This highlights the importance of a checklist system that incorporates counting the number of swabs at the start of surgery and again at the end to ensure none are left in the abdomen.
