AbstractSynovial lipomatosis has been described as a rare disease of the synovial membrane in humans. This report represents a synovial lipomatosis case of the left stifle joint in a dog, diagnosed by MRI and validated by histopathologic examination. Synovial lipomatosis can be difficult to recognise due to the absence of specific clinical features, especially in view of its similarity to other disorders with the benign or malignant origin in the synovial membrane. Therefore, the validation of this pathology could be essential in directing patient management. The aim of this report was to describe approaches required for the identification of synovial lipomatosis, such as clinical signs, diagnostic imaging characteristics and histological pattern, that have not been published previously in veterinary medicine.