Surg Today (2010) 40:176–180DOI 10.1007/s00595-008-4009-y

Reprint requests to: A. SasakiReceived: April 11, 2008 / Accepted: August 19, 2008

Laparoscopic Excision of Retroperitoneal Tumors: Report of Three Cases

AKIRA SASAKI1, TAKAYUKI SUTO

2, HIROYUKI NITTA1, OSAMU SHIMOOKI

3, TORU OBUCHI1, and GO WAKABAYASHI

1

1 Department of Surgery, Iwate Medical University School of Medicine, 19-1 Uchimaru, Morioka 020-8505, Japan2 Division of Surgery, Morioka Municipal Hospital, Morioka, Japan3 Division of Surgery, Iwate Prefectural Kuji Hospital, Kuji, Iwate, Japan

AbstractRetroperitoneal neural tumors are rarely excised lapa-roscopically, with fewer than ten cases reported in the literature. Between February 2005 and December 2007, we performed successful planned laparoscopic excision of retroperitoneal tumors using the four-trocar tech-nique in three patients. All three patients were women, with a mean age of 40.7 years. The mean tumor size was 4.8 cm. The mean operative time was 126 min and the mean blood loss 14.3 ml. The postoperative pathological diagnosis was schwannoma in one patient and ganglio-neuromas in two. There was no morbidity or mortality. Although diffi cult to diagnose preoperatively, neural tumors in the retroperitoneal space are most often benign, with a good prognosis. Laparoscopic surgical techniques for retroperitoneal tumors are safe, and their use is encouraged when an appropriate diagnosis is made, after exclusion of malignant subtypes.

Key words Laparoscopy · Retroperitoneal tumor · Schwannoma · Ganglioneuroma

Introduction

Retroperitoneal tumors usually enlarge silently, until compression of the surrounding organs produces symp-toms. Retroperitoneal tumors have traditionally been excised using a standard open technique: even malig-nant tumors with large vessel invasion can sometimes be removed completely.1 However, fewer than ten cases of laparoscopic excision of retroperitoneal neural tumors such as schwannoma and neurofi broma have been reported in the world literature to date.2–7

Histopathologic examination after laparotomy is often necessary to make a fi nal diagnosis because the lack of imaging features of retroperitoneal tumors makes pre-operative diagnosis diffi cult. We report three cases of laparoscopic excision of retroperitoneal tumors—one schwannoma and two ganglioneuromas—which resulted in excellent clinical outcomes.

Case Reports

Between February 2005 and December 2007, three patients with retroperitoneal tumors underwent laparo-scopic excision. The patients’ characteristics and post-operative diagnoses are summarized in Table 1. All three patients were women, with a mean age of 40.7 years. The mean tumor size was 4.8 cm. Laparoscopic excisions of the retroperitoneal tumors were completed successfully in all three patients. The operative data and clinical outcomes are summarized in Table 2. The mean operative time was 126 min and the mean blood loss 14.3 ml. There was no morbidity or mortality.

Case 1

A 69-year-old woman presented to our hospital for investigation of diarrhea and general fatigue. The patient’s medical history was remarkable in that she had undergone laparoscopic cholecystectomy for cholecys-titis and open colectomy for colonic cancer. Laboratory data and the levels of tumor markers were all within normal limits, and a functional endocrine tumor test was negative. Abdominal ultrasonography (US) and computed tomography (CT) showed a 5.5 × 3.8-cm, solid, well-circumscribed mass located anterior to the left psoas muscle (Fig. 1A). Operative excision was planned via laparoscopy, using an approach similar to that for left-sided colectomy, using the four-trocar tech-nique. Adhesiolysis of the abdominal wall was done and the descending colon was freed from the lateral gutter.

A. Sasaki et al.: Excision of Retroperitoneal Tumors 177

After opening the peritoneal membrane, a smooth whitish-yellow tumor was identifi ed, which was also adhered to the left ureter (Fig. 1B). We performed a complete laparoscopic excision. Histopathologic exami-nation revealed spindle cells distributed in a palisade with a degenerative pattern, representing hemorrhage, interstitial fi brosis, and cystic areas. Some atypical nuclei with very limited mitotic activity were observed. The tumor cells stained positively for S-100 protein and negatively for desmin and muscle-specifi c actin, which is consistent with a benign schwannoma. After 17 months of follow up, the patient was well with no signs of local recurrence.

Case 2

A 22-year-old woman presented to our hospital for investigation of epigastralgia. Physical examination was unremarkable. Laboratory data and the tumor markers were all within normal limits, and a functional endo-

crine tumor test was negative. Abdominal US showed a predominantly cystic mass located behind the lesser omental sac. Enhanced CT showed a 4 × 4-cm, well-circumscribed, low-density mass with a central high-density spot (Fig. 2A). Magnetic resonance imaging (MRI) showed hypointensity on T1-weighted images and hyperintensity on T2-weighted images. Laparos-copy was performed via an approach similar to that for gastrectomy, using the four-trocar technique. Intraop-eratively, a soft elastic tumor was identifi ed in the ret-roperitoneal space adjacent to the roof of the left gastric artery. The tumor appeared to be encapsulated and was easily dissected free from adjacent structures using lap-aroscopic coagulating shears. A complete laparoscopic excision was performed (Fig. 2B). Histopathologic examination revealed proliferation of well-differentiated ganglion cells and nerve fi bers. No mitosis or atypia was observed. The tumor cells stained posi-tively for S-100 protein, but were negative for desmin and muscle-specifi c actin, which is consistent with a

Table 1. Patient characteristics and postoperative diagnosis

No. Sex Age (years) Presentation Tumor size (cm) Diagnosis

1 F 69 Diarrhea 5.5 Schwannoma2 F 22 Epigastralgia 4 Ganglioneuroma3 F 31 Lower abdominal pain 5 Ganglioneuroma

Table 2. Operative data and clinical outcomes

No. Operative time (min) Blood loss (ml) Postoperative stay (days) Morbidity

1 95 15 11 None2 120 5 12 None3 163 23 4 None

A B

Fig. 1A,B. Case 1. A Contrast-enhanced computed tomography showing a 5.5-cm, solid, and well-circumscribed mass anterior to the left psoas muscle. B The tumor was adhered to the left ureter (arrow)

178 A. Sasaki et al.: Excision of Retroperitoneal Tumors

benign ganglioneuroma. After 36 months of follow up, the patient was well with no signs of local recurrence.

Case 3

A 31-year-old woman presented to our hospital for investigation of lower abdominal pain. Laboratory data and the tumor markers were all within normal limits, and a functional endocrine tumor test was negative. Abdominal US and CT revealed a 5.0 × 4.5-cm mass in the retroperitoneal space, between the inferior mesen-teric artery and the left psoas muscle (Fig. 3A). Magnetic resonance imaging showed a homogeneous hypointensity on T1-weighted images and hyperinten-

sity on T2-weighted images. Laparoscopy was per-formed via an approach similar to that for a left-sided colectomy, using the four-trocar technique. Intraopera-tively, a hard elastic tumor was identifi ed on the left para-aortic side, between the lumbar vertebrae and the left psoas muscle. The tumor appeared to be encapsu-lated and was adhered to the inferior mesenteric artery. The tumor was carefully dissected from the inferior mesenteric artery using laparoscopic coagulating shears, and a complete laparoscopic excision was performed (Fig. 3B). Histopathologic examination revealed the proliferation of spindle cells and large tumor ganglion cells, which were well differentiated and embedded in a neuromatous stroma. No mitosis or atypia was

A B

Fig. 2A,B. Case 2. A Contrast-enhanced computed tomogra-phy showing a 4-cm, well-circumscribed, and low-density mass with a central high-density spot. B The tumor was identifi ed

in the retroperitoneal space, adjacent to the roof of the left gastric artery

A B

Fig. 3A,B. Case 3. A Contrast-enhanced computed tomography showing a 5-cm mass in the retroperitoneal space, between the inferior mesenteric artery and the left psoas muscle. B The tumor was adhered to the inferior mesenteric artery

A. Sasaki et al.: Excision of Retroperitoneal Tumors 179

observed, which is consistent with a benign ganglioneu-roma. After 5 months of follow-up the patient was well, with no signs of local recurrence.

Discussion

Schwannoma is a neurogenic tumor that arises from the Schwann cells in the peripheral nerves. It develops most commonly in the head, neck, or extremities. Since patients are often asymptomatic, or have only vague abdominal pain, schwannomas may be identifi ed inci-dentally when other complaints are investigated, or they may grow very large before they cause overt symptoms. Das Gupta et al.8 reported that schwannoma occurs mainly in the cephalocervical region (44.8%), limbs (32.6%), and occasionally in the retroperitoneal space (0.7%). First described by Ackerman and Taylor in 1951, ancient schwannoma is a rare variant that consists almost entirely of Antoni type B tissue.9 Histopatho-logically, schwannoma may demonstrate a biphasic pattern with areas of highly cellular (Antoni type A) and myxoid matrix (Antoni type B) predominance. On MRI, schwannomas are seen as masses of hypointensity on T1-weighted images and hyperintensity on T2-weighted images.10 Schwannoma typically appears as a solitary, well-encapsulated mass, which is fi rm and round with a smooth surface. It is commonly identifi ed as the ancient variant.11 Establishing a preoperative diagnosis is not easy, although radiographic imaging is helpful in therapeutic planning, as it gives information about the size, location, and possible invasion of other structures. According to Nakashima et al., a tumor size larger than 5.5 cm, symptoms, the absence of calcifi ca-tions, irregular margins, and cystic degeneration or necrosis may all be predictors of primary retroperito-neal malignant tumors.12,13 Total excision is therapeutic and has a good prognosis; however, a local recur-rence rate of 10%–20% is attributed to incomplete excision.14,15

Ganglioneuromas are considered to be part of the neuroblastoma group, together with neuroblastomas and ganglioneuroblastomas.16,17 Arising along the sym-pathetic chain, ganglioneuromas are commonly local-ized in the posterior mediastinum, followed by the retroperitoneum, cervical region, and adrenal glands.17 Diffuse ganglioneuromatosis, which may affect any part of the gastrointestinal tract, has also been described,18 and may be associated with neurofi bromatosis or the syndrome of multiple endocrine neoplasia (MEN) type IIb.16 Additionally, composite pheochromocytoma/gan-glioneuroma of the adrenal gland, associated with MEN IIa, has been reported.19 Ganglioneuroma is a well-differentiated tumor, most commonly seen in children older than 10 years.20 Interestingly, Moschovi et al.21 and

Kulkarni et al.22 described the malignant transformation of dormant ganglioneuroma, and Drago et al.23 reported the spontaneous development of a malignant peripheral nerve-sheath tumor in benign ganglioneuroma. Thus, careful monitoring may be necessary after the resection of benign retroperitoneal tumors.

In conclusion, neural tumors in the retroperitoneal space are most often benign and have a good prognosis, although they are diffi cult to diagnosis preoperatively. Laparoscopic surgical techniques for retroperitoneal tumors are safe, and their use is encouraged when an accurate and appropriate diagnosis is made, after the exclusion of malignant subtypes.

References

1. Shindo S, Motohashi S, Katsu M, Kaga S, Inoue H, Matsumoto M, et al. Treatment of abdominal malignancy invading the vena cava: a report of seven cases. Surg Today 2007;37:685–9.

2. Ohigashi T, Nonaka S, Nakanoma T, Ueno M, Deguchi N. Lapa-roscopic treatment of retroperitoneal benign schwannoma. Int J Urol 1999;6:100–3.

3. Kawabata G, Mizuno Y, Okamaoto Y, Nomi M, Hara I, Okada H, et al. Laparoscopic resection of retroperitoneal tumors: report of two cases (in Japanese). Hinyoukika Kiyo 1999;45:691–4.

4. Nishio A, Adachi W, Igarashi J, Koide N, Kajikawa S, Amono J. Laparoscopic resection of a retroperitoneal schwannoma. Surg Laparosc Endosc Percutan Tech 1999;9:306–9.

5. Descazeaud A, Coggia M, Bourriez A, Goëau-Brissonnière O. Laparoscopic resection of a retroperitoneal schwannoma. Surg Endosc 2003;17:520.

6. Johna S, Shalita T, Johnson W. Laparoscopic-assisted resection of a large retroperitoneal tumor. JSLS 2004;8:287–9.

7. Funaizumi N, Sasaki A, Matsumoto T, Inomata M, Shiraishi N, Kitano S. Laparoscopic resection of a retroperitoneal schwannoma behind the lesser omental sac. Surg Laparosc Endosc Percutan Tech 2004;14:175–7.

8. Das Gupta TK, Brasfi eld RD, Strong EW, Hajdu SI. Benign soli-tary schwannoma (neurilemomas). Cancer 1969;24:355–66.

9. Ackerman LV, Taylor FH. Neurogenous tumors within the thorax: a clinicopathological evaluation of forty-eight cases. Cancer 1951;4:669–91.

10. Cerofolini E, Landi A, DeSantis G, Maiorana A, Canossi G, Romagnoli R. MR of benign peripheral nerve sheath tumors. J Comput Assist Tomogr 1991;15:593–7.

11. Gilio M, Giasotto V, Medica M, Germinale F, Durand F, Quei-rolo G, et al. Retroperitoneal ancient schwannoma: a case report and analysis of clinico-radiological fi ndings. Ann Urol (Paris) 2002;36:104–6.

12. Nakashima J, Ueno M, Nakamura K, Tachibana M, Baba S, Deguchi N, et al. Differential diagnosis of primary benign and malignant retroperitoneal tumors. Int J Urol 1997;4:441–6.

13. Cothern CC, Lutfi yya WL, Kim FJ, Ciesla DJ. Image of the month; schwannoma. Arch Surg 2006;141:941–2.

14. Daneshmand S, Youssefzadeh D, Chamie K, Boswell W, Wu N, Stein JP, et al. Benign retroperitoneal schwannoma: a case series and review of the literature. Urology 2003;62:993–7.

15. Tortorelli AP, Papa V, Rosa F, Pacelli F, Doglietto GB. Image of the month; retroperitoneal schwannoma. Arch Surg 2006;141:1259–61.

16. Modha A, Paty P, Bilsky MH. Presacral ganglioneuromas. Report of fi ve cases and review of the literature. J Neurosurg Spine 2005;2:366–71.

180 A. Sasaki et al.: Excision of Retroperitoneal Tumors

17. Cerullo G, Marrelli D, Rampone B, Miracco C, Caruso S, Di Martino M, et al. Presacral ganglioneuroma: a case repot and review of literature. World J Gastroenterol 2007;13:2129–31.

18. Freeman BD, Zuckerman GR, Callery MP. Duodenal ganglio-neuroma: a rare cause of upper gastrointestinal hemorrhage. Am J Gastroenterol 1996;91:2626–7.

19. Brady S, Lechan RM, Schwaitzberg SD, Dayal Y, Ziar J, Tischler AS. Composite pheochromocytoma/ganglioneuroma of the adrenal gland associated with multiple endocrine neoplasia 2A: case report with immunohistochemical analysis. Am J Surg Pathol 1997;21:102–8.

20. Jain M, Shubha BS, Sethi S, Banga V, Bagga D. Retroperitoneal ganglioneuroma: report of a case diagnosed by fi ne-needle aspira-

tion cytology, with review of the literature. Diagn Cytopathol 1999;21:194–6.

21. Moschovi M, Arvanitis D, Hadjigeorgi C, Mikraki V, Tzortzatou-Stathopoulou F. Late malignant transformation of dormant gan-glioneuroma? Med Pediatr Oncol 1997;28:377–81.

22. Kulkarni AV, Bilbao JM, Cusimano MD, Muller PJ. Malignant transformation of ganglioneuroma into spinal neuroblastoma in an adult. Case report. J Neurosurg 1998;88:324–7.

23. Drago G, Pasquier B, Pasquier D, Pinel N, Rouault-Plantaz V, Dyon JF, et al. Malignant peripheral nerve sheath tumor arising in a “de novo” ganglioneuroma: a case report and review of the literature. Med Pediatr Oncol 1997;28:216–22.