P09.10: Unilateral pulmonary agenesis: prenatal and postnatal findings and management

Schwannomas are nerve sheath tumors that are most often benign in nature. These tumors rarely occur in the retroperitoneum, where they are found in 0.5 to 5% of cases. Presenting signs are varied and non-specific and accurate pre-operative diagnosis of the tumor is difficult despite the use of various imaging techniques. Schwannomas suspected as gynecologic masses have been reported, but there have been few reports of benign retroperitoneal schwannomas in pregnancy. We present a case of an asymptomatic 33-year old primigravida, found to have a pelvic mass during the 1st trimester ultrasound scan. On the basis of this incidental finding, she underwent magnetic resonance imaging; the diagnosis was a retroperitoneal tumor thought to arise from the sacral plexus, and expectant management followed. During the 3rd trimester there was worsening of symptoms, increased pain in the left flank region and pain on walking. She underwent another MRI; there was no progression of tumor growth. Ultrasound examination prior to delivery showed the tumor at the level of the cervix in the left presacral region. On palpation there was tenderness in this region, but no palpable mass. She underwent an uncomplicated Cesarean section in the 37th week of gestation. One month later she was admitted to the department of neurosurgery, and underwent surgery, with complete excision of the tumor that was found to be a benign schwannoma on pathology.