Case of the week 4.13.20
Publication Date: 2020-04-13
History
8 year old mixed breed dog. History of femoral fracture when 1 year old, surgically corrected.
2 images
Findings
Orthogonal radiogaphs of the left femur are available for interpretation.
A bone plate with 10 associated screws is present along the lateral aspect of the left femur. Additionally, there are 3 cerclage wires around the mid aspect of the femoral diaphysis.
Arising from the distal femoral diaphysis and metaphysis, there is a large, expansile, predominantly osteolytic mass with amorphous peripheral periosteal proliferation. There is marked moth-eaten lysis of the mid femoral diaphysis. At the level of the 3rd and 4th from distal screws, there is an elongated moth-eaten osseous fragment arising frp, the caudal cortex (approximately 3.1 cm in length and 0.7 cm in width). The aggressive lesion stops at the level of the physeal scar of the distal femur, and neither the patella nor the fabellae are affected.
There is severe regional soft tissue and muscular swelling surrounding this mass. The popliteal lymph node is moderately enlarged and lobular. The visible proximal tibia displays coarse trabeculation.
Diagnosis
- Monostotic, aggressive, expansile, primarily osteolytic, mass of the distal left femur with prior internal fixation is most consistent with implant associated sarcoma. - The enlarged left popliteal lymph node may be metastatic or reactive. - Disuse osteopenia of the left tibia.
Discussion
Thoracic radiographs should be performed for evidence of pulmonary metastasis.
Cytology was consistent with osteosarcoma
Litterature
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5281555/
Notes
Case originally seen by Dr. Morandi