Desmoid tumours are uncommon benign tumours that arise from the musculoaponeurotic layers. They're also known as aggressive fibromatosis, and they make up roughly 3% of all soft tissue tumours and 0.3% of all neoplasms. They have no metastatic potential, yet they have a strong proclivity to invade and recur locally. Patients between the ages of 30 and 40 are most typically diagnosed, with a female preponderance. 75-80% of cases are spontaneous, whereas the remainder are linked to familial adenomatous polyposis (FAP). Herewith, we have presented a case report of 37-year-old female patient presented to the surgical oncology outpatient department with a 15-month history of pain in the right side of her lower abdomen, followed by 8-month complaints of swelling in the same area. A lump was felt in the right paramedian region on clinical examination, which shrank in size when the patient raised his legs straight.