Management of A Desmoid Tumor in Pregnancy: A Case Report

A desmoid tumor is a rare, non-metastasizing, locally aggressive, monoclonal proliferative disease of fibroblastic origin with a high recurrence rate. The etiology remains unclear. Desmoid tumors can be found in the abdominal wall, abdominal cavity, trunk and limbs. When sporadic, the abdominal wall is the most common site, particularly around the rectus abdominis muscle, with tumors tending to develop in young women of reproductive age or those who have suffered trauma, principally pregnant or postpartum women. Due to its unpredictable clinical course and high recurrence rate, the exclusive use of resection with a wide safety margin, the treatment of choice in cases of advanced tumors, has been questioned. This paper describes a case of a large desmoid tumor on the abdominal wall that developed in the 10th week of pregnancy in a 29-year-old patient with no history of familial adenomatous polyposis. Ultrasound showed that the tumor had increased around 158% during pregnancy. The patient underwent Cesarean section during which a mass of around 20 cm was detected between the anterior and posterior layer of the aponeurosis of the rectus abdominis muscle. Conservative management (no intervention) was adopted with follow-up imaging. Ultrasound-guided core biopsy was performed four and a half months after delivery, with histopathology revealing a spindle cell neoplasm, with possible musculoaponeurotic fibromatosis. Six months after childbirth, the tumor had decreased spontaneously by 40.5% in thickness and nine months following delivery the patient continues to be monitored under expectant management, with no complaints or symptoms. Although rare, obstetricians should be aware of the possibility of a desmoid tumor during pregnancy and should evaluate the best management option (surgery, pharmacological treatment or expectant management) according to the patient’s profile in order to avoid visceral complications, the need for extensive surgery with possible aesthetic and functional sequelae, and even iatrogenic complications.