Surgical management of retroperitoneal pelvic schwannoma: experiences with four cases and review of literature

Schwannomas generally occur in the head, neck, and extremities; however, its occurrence in the retroperitoneal pelvic space is rare. Here, we describe four successful surgical managements of retroperitoneal pelvic schwannoma which was identified in preoperative imaging studies. Computed tomography demonstrated heterogeneous masses in the retroperitoneum with well-defined margins. The retroperitoneal pelvic schwannomas were removed by complete excision or enucleation through either laparotomy or laparoscopy. The diagnoses of schwannoma were further confirmed via histopathology. Postoperatively, two patients had transient but minimal neurologic deficits in a lower extremity. No evidence of tumor recurrence was detected over a 12-month following-up of four patients. A meticulous review of three-dimensional imaging studies provided correct preoperative diagnoses of schwannomas. Postoperative neurologic deficits may be less serious than expected. Complete resection of the tumor is the treatment of choice, and recurrence is unusual.

Pelvic neoplasm; Retroperitoneum; Schwannoma; Neurologic deficits.

[1] Ningshu L., Min Y., Xieqiao Y., Yuanqing Y., Xiaoqiang M., Rubing L.: “Laparoscopic management of obturator nerve schwannomas: experiences with 6 cases and review of the literature”. Surg. Laparosc. Endosc. Percutan. Tech., 2012, 22, 143.

[2] Cury J., Coelho R.F., Srougi M.: “Retroperitoneal schwannoma: case series and literature review”. Clinics (Sao Paulo), 2007, 62, 359.

[3] Hoarau N., Slim K., Da Ines D.: “CT and MR imaging of retroperi-toneal schwannoma”. Diagn. Interv. Imaging., 2013, 94, 1133.

[4] Li Q., Gao C., Juzi J.T., Hao X.: “Analysis of 82 cases of retroperi-toneal schwannoma”. ANZ. J. Surg., 2007, 77, 237.

[5] Osman S., Lehnert B.E., Elojeimy S., Cruite I., Mannelli L., Bhar-gava P., et al.: “A comprehensive review of the retroperitoneal anatomy, neoplasms, and pattern of disease spread”. Curr. Probl. Diagn. Radiol., 2013, 42, 191.

[6] Clark M.A., Fisher C., Judson I., Thomas J.M.: “Soft-tissue sarcomas in adults”. N. Engl. J. Med., 2005, 353, 701.

[7] Zhu Z., Zhao X., Zhao Y., Yang L., Zhao J., Dai J., et al.: “Evalua-tion of CT findings for the differentiation of benign from malignant primary retroperitoneal tumors”. Chin. Med. J. (Engl.), 2014, 127, 114.

[8] Van Roggen J.F., Hogendoorn P.C.: “Soft tissue tumours of the retroperitoneum”. Sarcoma, 2000, 4, 17.

[9] Chandhanayingyong C., Asavamongkolkul A., Lektrakul N., Muangsomboon S.: “The management of sacral schwannoma: report of four cases and review of literature”. Sarcoma., 2008, 2008, 845132.

[10] Goh B.K., Tan Y.M., Chung Y.F., Chow P.K., Ooi L.L., Wong W.K.: “Retroperitoneal schwannoma”. Am. J. Surg., 2006, 192, 14.

[11] Khatib R.A., Khalil A.M., Saba M.I., Aswad N.K., Mroueh A.M.: “A pelvic retroperitoneal Schwannoma presenting as an adnexal mass”. Gynecol. Oncol., 1994, 53, 242.

[12] Lee D.Y., Chi J.Y., Seok J., Han S., Lee M.H., Jeong W.J., et al.: “Feasibility of brachial plexus schwannoma enucleation with intraoperative neuromonitoring”. Clin. Exp. Otorhinolaryngol., 2020, 13, 203.

[13] Sasaki H., Nagano S., Yokouchi M., Setoguchi T., Shimada H., Ya-mamoto T., et al.: “Utility of intraoperative monitoring with motorevoked potential during the surgical enucleation of peripheral nerve schwannoma”. Oncol. Lett., 2018, 15, 9327.

[14] Di Furia M., Salvatorelli A., Della Penna A., Vicentini V., Sista F., Chiominto A., et al.: “Advantage of laparoscopic resection for pelvic Schwannoma: Case report and review of the literature”. Int. J. Surg. Case. Rep., 2018, 45, 38.

[15] Park N.Y., Chong G.O., Lee Y.S.: “Laparoscopic resection of schwannoma in the anomaly of obturator nerve”. J. Laparoendosc. Adv. Surg. Tech. A., 2007, 17, 769.

[16] Hamada Y., Iwaki T., Fukui M., Tateishi J.: “A comparative study of embedded nerve tissue in six NF2-associated schwannomas and 17 nonassociated NF2 schwannomas”. Surg. Neurol., 1997, 48, 395.

[17] Daneshmand S., Youssefzadeh D., Chamie K., Boswell W., Wu N., Stein J.P., Boyd S., Skinner D.G.: “Benign retroperitoneal schwan-noma: A case series and review of the literature”. Urology, 2003, 62, 993-997.

[18] Inoue T., Kato H., Yoshikawa K., Adachi T., Etoh K., Wake N.: “Retroperitoneal schwannoma bearing at the right vaginal wall”. J. Obstet. Gynaecol. Res., 2004, 30, 454-457.

[19] Song J.Y., Kim S.Y., Park E.G., Kim C.J., Kim D.G., Lee H.K., Park I. Y. “Schwannoma in the retroperitoneum”. J. Obstet. Gynaecol. Res., 2007, 33, 371-375.

[20] Surendrababu N.R., Cherian S.R., Janakiraman R., Walter N.: “Large retroperitoneal schwannoma mimicking a cystic ovarian mass in a patient with hansen’s disease”. J. Clin. Ultrasound, 2008, 36, 318-320.

[21] Sinha R., Sundaram M., Hegde A., Mahajan C.: “Pelvic schwannoma masquerading as broad ligament myoma”. J. Minim. Invasive. Gynecol., 2008, 15, 217-219.

[22] Dawley B.: “A retroperitoneal femoral nerve schwannoma as a cause of chronic pelvic pain”. J. Minim. Invasive. Gynecol., 2008, 15, 491-493.

[23] Choudry H.A., Nikfarjam M., Liang J.J., Kimchi E.T., Conter R., Gusani N.J., Staveley-O’Carroll K.F.: “Diagnosis and management of retroperitoneal ancient schwannomas”. World J. Surg. Oncol., 2009, 7, 12.

[24] Tryggvason G., Barnett A., Kim J., Soken H., Maley J., Hansen M. R.: “Radiographic association of schwannomas with sensory ganglia”. Otol. Neurotol., 2012, 33, 1276.

[25] Ramage J.L., Varacallo M.: “Anatomy, Bony Pelvis and Lower Limb, Medial Thigh Muscles”. Treasure Island: StatPearls Publishing; 2018.