May's Case of the Month
Suspected Osteosarcoma in a
Feline Pelvis
Dr. Kara Woody
Patient Information:
Age: 6 years
Gender: Neutered Male
Breed: DSH
Species: Feline
History:
Presented for straining to defecate and vomiting.
Radiographic Findings:
A lytic left ileal mass and constipation was identified on radiographs.
Ultrasonographic Findings:
A heterogenous mixed echogenic mildly cavitated mass was visualized associated with the left ileum measuring ~1.5x4.0cm.
Abdominal Ultrasound Interpretation:
Bone Mass-the findings are moderate-DDX: neoplasia (osteosarcoma vs histiocytic sarcoma vs other) vs osteomyelitis (fungal vs bacterial)
Further diagnostics:
Heavy sedation was used and fine needle aspirate was performed of the pelvic mass and submitted to Casey J. LeBlanc DVM, PhD, Diplomate, ACVP (Clinical Pathology). Cytology results were 75% confident for sarcoma based on a low number of mesenchymal cells exhibiting malignant criteria. Osteosarcoma was the top differential. Biopsy and histopathology was recommended for definitive diagnosis.
Case Update:
Patient was referred to oncology for further case management. Surgery is currently being considered.
Discussion:
Osteosarcoma is less common in cats than dogs, but is still the most common bone tumor in this species. Generally, it behaves less aggressively than in dogs, but metastasis can occur. Surgery is the treatment of choice with chemotherapy being appropriate in some cases.
Lateral radiograph showing lytic ileal lesion (circled in red) and associated constipation.
Ultrasonographic image of heterogenous mass (middle of image) associated with pelvic bone (structure with complete distal acoustic shadowing on the right of image)
A large individual cell with a large eccentric nucleus consistent with osteosarcoma surrounded by peripheral blood.
Thank you to Banfield Pembroke and Eastern VetPath for collaborating with us on this interesting case.