Soft tissue sarcomas are a diverse group of cancers arising from connective tissues such as fat, muscle, fibrous tissue, nerves, and blood vessel walls. Despite their varied cell origins, these tumours share similar biological behaviour: they grow as locally invasive masses that infiltrate surrounding tissues along fascial planes, making them appear smaller on the surface than they truly are beneath the skin. Grade I–II tumours grow relatively slowly and have a low chance of spreading to distant organs, but they can recur locally if surgical margins are not wide enough. The key to successful treatment is achieving complete surgical removal with generous margins at the first operation, as recurrences tend to be more difficult to excise completely. Large breed dogs are generally overrepresented, and these tumours most commonly appear on the trunk or extremities.