A case of retroperitoneal schwannoma discovered during laparoscopic surgery performed for suspected gossypiboma

Abstract

  We report here a case of retroperitoneal schwannoma histopathologically diagnosed after laparoscopic surgery. This surgery was initially performed for suspected gossypiboma based on preoperative diagnostic imaging (MRI and CT). The patient was a 62-year-old female with gravida 2 and para 2. When she was 32 years old, she underwent extirpation of a right ovarian tumor via laparotomy. In August 2008, she presented to her primary physician with a chief complaint of constipation and gastric discomfort. Abdominal ultrasound showed a tumor of φ 2.9 x 3.5 cm in the left lower quadrant. The patient was referred to our department with a suspicion of left ovarian tumor. CT and MRI revealed a mass of φ 3.0 x 2.0 x 2.0 cm in the left iliac fossa. The mass had a regular margin. In both CT and MRI T1-weighted images, its central region had areas with low signal intensity and without dense enhancement. In MRI T2-weighted images, the mass showed high intensity. The mass was located in an unusual site for an ovarian tumor, and gossypiboma was suspected because the patient had a history of laparotomy with right ovarian resection. Laparoscopic surgery was selected to minimize as much as possible physical stress on the patient. Laparoscopy revealed a reddish brown protrusion (diameter: 3 cm) near the left iliopsoas muscle. The retroperitoneum was incised and then opened bluntly with grasping forceps. A grayish white mass with a smooth surface which was connected to cord-like tissue was found. Intraoperative rapid histological diagnosis was retroperitoneal schwannoma. Postoperatively, the patient complained of decreased sensation of the lateral left thigh (femoral nerve territory) but there was no decrease in motor function. In this patient, gossypiboma was initially suspected from diagnostic imaging and because of the patient's surgical history. However, this case indicates that when a tumor occurs in an unusual site, it is necessary to consider retroperitoneal schwannoma in the preoperative differential diagnosis.