Proteus syndrome is an extremely rare congenital disorder that produces multifocal overgrowth of tissue.This report presents a surgical case of a large lipoma in the abdominal wall of a patient with Proteus syndrome.She was diagnosed with Proteus syndrome based on certain diagnostic criteria.The neoplasm increased in size gradually,producing hemihypertrophy of her left lower extremity and trunk,and spread to her retroperitoneum and her left abdominal wall.She experienced gradually progressive constipation,nausea,vomiting,and abdominal pain.Computed tomography (CT) of the abdomen demonstrated a large mass in the subcutaneous adipose tissue of the left lower abdominal wall which measured 12 cm × 8 cm x 6 cm in diameter and encased the left colon.This mass in the abdominal wall was excised.The weight of the excised mass was 1550 g.The histopathological diagnosis of this mass was lipoma.After surgery,the encasement of the left colon was improved,and the patient was able to move her bowels twice per day.The excision of the large lipoma in the abdominal wall contributed to the improved bowel passage in this patient with Proteus syndrome. Proteus syndrome is an extremely rare congenital disorder that produces multifocal overgrowth of tissue. This report presents a surgical case of a large lipoma in the abdominal wall of a patient with Proteus syndrome. The was was diagnosed with Proteus syndrome based on certain diagnostic criteria. The neoplasm increased in size gradually, producing hemihypertrophy of her left lower extremity and trunk, and spread to her retroperitoneum and her left abdominal wall. history of progressive progressive stimulation, nausea, vomiting, and abdominal pain. Computed tomography (CT) of the abdomen demonstrated a large mass in the subcutaneous adipose tissue of the left lower abdominal wall which measured 12 cm × 8 cm × 6 cm in diameter and encased the left colon.This mass in the abdominal wall was excised.The weight of the excised mass was 1550 g. The histopathological diagnosis of this mass was lipoma. After surgery, the encasement of the left colon was improved, and the patient was able to move her bowels twice per day. The excision of the large lipoma in the abdominal wall contributed to the improved bowel passage in this patient with Proteus syndrome.