Rapid progression of a pregnancy-associated intra-abdominal desmoid tumor in the post-partum period: A case report

INTRODUCTION: The clinical behavior of desmoid tumors can be unpredictable, particularly when they arise in the ante-partum or post-partum period. We present a case of an intra-abdominal desmoid tumor that was identified in the ante-partum period, progressed rapidly in the post-partum period, and was subsequently resected. PRESENTATION OF CASE: The patient is a 19 year-old female who was found to have a 12 cm intra-abdominal mass on a fetal assessment ultrasound. The decision was made to observe the patient and monitor the mass for growth. However, the mass rapidly grew in the post-partum period. The patient was transferred to our institution after an exploratory laparotomy revealed a large intra-abdominal mass emanating from the small bowel mesentery. The 30 cm × 24 cm × 16 cm mass was successfully resected with negative margins, and the pathologic diagnosis of desmoid tumor was confirmed. The patient had an uncomplicated post-operative course and was discharged on post-operative day 6. DISCUSSION: The majority of pregnancy-associated desmoid tumors are in the abdominal wall, arising from the rectus abdominus muscle or from previous Cesarean section scars. These tumors may spontaneously regress in the post-partum period and therefore, patients with these tumors are often observed. Close follow-up is important so that rapid tumor progression, which may lead to unresectability, can be identified and managed appropriately. CONCLUSION: A patient with a rare case of a giant pregnancy-associated, intra-abdominal desmoid tumor that rapidly progressed in the post-partum period and was successfully treated with surgical resection with negative margins.