Synovial metastases are rare for any malignancy. This case report discusses a case of synovial metastasis from urothelial carcinoma of the renal pelvis presenting with recurrent hemarthrosis. The diagnosis of malignant synovitis can be obtained by synovial fluid aspiration, which is a quick and minimally invasive method, especially when imaging is unyielding or unspecific. Unfortunately, the diagnosis is associated with a poor prognosis of about five months, and treatment is often palliative. While no clinical guidelines exist, a multimodal and multidisciplinary management approach can help address the physical and psychosocial losses suffered.