Introduction

Osteosarcoma - the most common (over 80%) histopathological type of bone tumors in the dog - is the primary malignant tumor that arises in the medullary cavity. The production of osteoid and immature bone by malignant osteoblasts is typical for such neoplasms. A major predisposing factor in their development is the size of the dog (the risk in giant dogs is 60,9 times the risk in small breeds, in large - 7,9 times). Male dogs are affected more often than females. Osteosarcomas in dogs have very strong site preferences: 68% of tumors occur in long bones.

Material and Methods

Four-year-old, intact female French bulldog was presented with slight lameness of left hind limb. Cranial cruciate ligament rupture was diagnosed, and the dog underwent knee surgery. Three months after surgery, the dog was presented again with the same leg lameness. The region of left calcaneus was swollen and painful. Based on biopsy, initial diagnosis of osteosarcoma was made, and decision of the leg amputation was made.

Results

After surgical treatment, histopathological examination was performed (formalin-fixed paraffin slides, decalcified, H&E stain). The final diagnosis was combined pattern of osteosarcoma (fibroblastic and osteoblastic type) with osteoid, irregularly deposited and formed in sheets.

Conclusions

Osteosarcoma of calcaneus in small-breed dog is rare and unexpected reason of lameness.