Sarah Boston, DVM, DVSc, DACVS, ACVS Founding Fellow of Surgical Oncology, University of Florida
Andre R. Spiguel, MD, University of Florida
Sarah Boston, DVM, DVSc, DACVS, ACVS Founding Fellow of Surgical Oncology, is an associate professor of surgical oncology at University of Florida. She earned her DVM from Western College of Veterinary Medicine in Saskatoon, Saskatchewan, Canada, and completed a rotating internship and residency at University of Guelph. Past president of Veterinary Society of Surgical Oncology, Dr. Boston has authored numerous articles on surgical oncology and speaks nationally and internationally on the topic. She is a cancer survivor and the author of Lucky Dog: How Being a Veterinarian Saved my Life.
Andre R. Spiguel, MD, is an assistant professor in the orthopedic surgery department and is on the musculoskeletal oncology team at University of Florida. He earned his MD from Pritzker School of Medicine at University of Chicago before completing a residency in orthopedic surgery at University of Chicago Medical Center. He completed fellowships in musculoskeletal oncology and orthopedic trauma at University of Chicago and Washington University, respectively. Dr. Spiguel’s clinical practice involves the treatment of bone and soft-tissue sarcomas of the extremities and pelvis, and he specializes in complex extremity reconstructions for limb salvage surgeries after tumor resection.
This column co-presents clinical cases in a side-by-side format, with the patient—human or veterinary—as the primary variable. It is the hope of the Clinicians Brief team that readers will see the inherent commonalities in managing cases of similar diseases, regardless of species.
The Zoobiquity series is based on Zoobiquity by Barbara Natterson-Horowitz and Kathryn Bowers.
A 10-year-old spayed rottweiler with a 2-week history of left pelvic limb lameness and a palpable mass over the left ilium was referred after fine-needle aspiration findings were consistent with a mesenchymal sarcoma, most likely osteosarcoma.
On physical examination, the patient continued to show mild left pelvic limb lameness. There was a 10-to-12cm hard palpable mass overlying the left ilium. The physical examination was otherwise unremarkable.
CBC, serum chemistry profile, and urinalysis results were unremarkable. Three-view thoracic radiographs showed no evidence of gross metastatic disease. A CT scan of the chest, abdomen, and pelvis showed an aggressive bone lesion of the left ilium, compatible with osteosarcoma, with tumor extension to the surrounding soft tissue (Figure 1). A full-body bone scan was performed. Static images were obtained 2 hours after intravenous injection of Tc99m-MDP. There was marked uptake in the area of the primary tumor (ie, the left ilium). There was also a possible metastatic lesion in the left costal cartilages; however, careful review of the CT scan showed that the increased uptake of radiopharmaceutical at that site was most likely consistent with old trauma rather than metastatic disease (Figure 2).
Left ileectomy and stereotactic radiosurgery were suggested to provide curative-intent local control of the tumor. Palliative radiation was also discussed. The owners elected ileectomy and preservation of the left pelvic limb; the left ilium was resected via sacroiliac disarticulation (Figure 3), and the left acetabulum and left pelvic limb were preserved. Postoperative radiographs showed adequate tumor removal (Figure 4).
The patient recovered well from surgery in the intensive care unit. She was managed postoperatively with fentanyl (2-5 g/kg/hr CRI) and meloxicam (0.1 mg/kg IV q24h). The dog was walking well with minimal support within 24 hours and was discharged 48 hours postoperatively on meloxicam (0.1 mg/kg PO q24h) and tramadol (3 mg/kg PO q8-12h).
The specimen was inked to assess the margins and submitted for histopathology. Histopathology confirmed a diagnosis of osteosarcoma. The mitotic index was 32 mitotic figures per 10 high-power (400) fields, with moderate-to-marked anisocytosis and anisokaryosis. The margins of excision were complete. Chemotherapy with single-agent carboplatin (6 doses at 300 mg/m2 IV) was initiated and was well tolerated without complication. At 136 days postsurgery, the patient showed no evidence of local recurrence or metastatic disease on pelvic and thoracic radiographs, respectively, and was ambulating well (see Video).
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