Endometrial stromal sarcoma (ESS) is a rare, malignant tumor of the endometrium. Low-grade endometrial stromal sarcoma (LG-ESS) is a less aggressive subtype of ESS that rarely metastasizes to the heart and large blood vessels. In the present study, we report a case of recurrent LG-ESS after treating the initial mass in the uterus six years ago in a 49-year-old female who presented with a four-month history of dyspnea and easy fatigability. Investigations revealed a right pulmonary embolism, suspicious right psoas muscle mass, and a large inferior vena cava (IVC) thrombus. One month later, she presented with multiple gastrointestinal symptoms and weight loss. Investigations then showed the development of a new right atrial mass, infra-diaphragmatic metastatic lymphadenopathy, progression of the presacral soft tissue component, invasion of the ileal bowel loop, and a tumoral thrombus in the IVC besides new metastatic lymphadenopathy and pulmonary metastasis. Therefore, a multidisciplinary team, which had a crucial role in this complicated case, decided to commence chemotherapy treatment. Such an unusual aggressive metastatic course of LG-ESS is limited in the literature; herein, we recognize a rarely documented disease.