Laparoscopic resection of a retroperitoneal pelvic schwannoma
A 54-year-old woman was referred to our hospital with a mass in the pelvic cavity detected on chest-abdominal, CT done for investigation of breast cancer. She had no particular past and family history, and the physical examination was unremarkable. Ultrasonography of the pelvis revealed a 5 × 4.3 cm, solid mass separated from her right adnexa (Fig. ). Contrast enhanced-CT showed a 5 × 4 cm, solid, well-defined, heterogeneous mass in the right side of the pelvic cavity (Fig. ). MRI showed that the tumor demonstrated homogeneous hypointensity on T1-weighted images and heterogeneous slight hyperintensity on T2-weighted images (Fig. a and b). Sagittal sections of MRI demonstrated that the mass was intricately related to the anterior presacral fascia (Fig. ). The preoperative diagnosis was a mesenteric gastrointestinal stromal tumor.\nUnder general anesthesia, the patient was placed in the supine position, and a 4-port technique was used. A 12-mm port was inserted through an umbilical incision for the placement of a flexible laparoscope. Three other ports (one 12-mm and two 5-mm ports for retraction or the working port) were placed. The left-sided port was mainly used for retraction. An initial incision was made in the retroperitoneum, and mainly sharp dissection by Liga-Sure was used to isolate the mass from the surrounding tissues. With careful dissection using sharp and blunt maneuvers, the mass was dissected from the neighboring vessels, such as the right internal iliac vessels and ureter (Fig. ). Although the ureter was easily identified and dissected free, the mass strongly adhered to the right internal iliac vessels, making its dissection difficult. Sponge dissection was very useful in that situation. Once free from the surrounding tissues, the mass was placed into a plastic bag to avoid spillage into the abdomen. It was then received through the enlarged incision of the umbilicus. A suction drainage tube was placed into the pouch of Douglas through a 12-mm port in the right side of the abdomen.\nThe intra-operative blood loss was minimal, and the operation time was 150 min. The specimen was an elastic hard, 5 × 4 cm mass with an integral envelope. On sectioning, it was yellow and white in color, predominantly solid with cystic change (Fig. ). Pathologic examination showed whorls and interlacing fascicles of schwannoma spindle cells, along with alternating Antoni-A and -B patterns with areas of hyalinization and fibrinoid degeneration (Fig. a and b). The cells stained positive for S-100 protein and negative for desmin and muscle-specific actin, consistent with a benign schwannoma. The patient had an uneventful post-operative course and was discharged on the fourth post-operative day. The patient has had no evidence of recurrence so far, 20 months after surgery.