Retroperitoneal leiomyosarcoma in a young adult presenting as a huge abdominal mass

Retroperitoneal sarcomas are rare tumors accounting for only 1-2% of all solid malignancies. Only 10-20% of sarcomas are retroperitoneal sarcomas, and the overall incidence is 0.3-0.4%/100,000 of the population. The peak incidence is in the fifth decade of life. These tumors grow very large as they have a very large retroperitoneal space to grow and producing very vague and mild symptoms like abdominal fullness and pain. We are hereby presenting a case of a 24-year-old female who presented with increasing abdominal girth, intermittent abdominal discomfort, palpable abdominal mass, and a 5 kg weight loss.