Case Report: Thoracic wall reconstruction using a partial latissimus dorsi muscle flap following en bloc resection of a large, progressive rib osteochondroma in a dog.

Osteochondroma is an exceedingly rare tumor in dogs, and surgical excision is recommended because of its potential for malignant transformation. A rib osteochondroma was incidentally identified in a 2-year-and-5-month-old mixed-breed dog during treatment for anemia. Computed tomography revealed a lesion originating from the right fourth rib that extended into the thoracic cavity, displacing the heart and major vessels to the left. Punch biopsy findings were consistent with chondroma. Surgical treatment consisted of en bloc excision with a 3-cm margin, including complete resection of the right fourth rib and the distal one-third of the fifth rib. No invasion of intrathoracic organs was observed. The resulting thoracic wall defect was reconstructed using a V-shaped partial latissimus dorsi muscle flap, which was anchored to the deep pectoral and external abdominal oblique muscles. Removal of the mass restored normal anatomical positioning of the displaced cardiac and mediastinal structures. Postoperative recovery was uneventful, with no respiratory compromise or surgical site complications. Histopathologic examination confirmed the diagnosis of osteochondroma. At the 15-month follow-up, radiographs showed no evidence of recurrence, and the dog remained clinically normal. This report describes successful thoracic wall reconstruction using a partial latissimus dorsi muscle flap without complete mobilization of the entire muscle following rib tumor resection in a dog.