RS3PE Syndrome is an inflammatory disease which affects mainly males and responds, rapidly, to low dose steroids. We describe the concurrence of RS3PE, poorly responsive to low dose steroids, and endometrial adenocarcinoma. In this patient, clinical and laboratory signs of RS3PE disappeared after total hysterectomy. Patients with RS3PE, poorly responsive to low dose steroids, need an accurate clinical and laboratory evaluation before considering the disease as idiopathic.