Yonago Acta medica 2014;57:129–132

Original Article

Surgical Treatment of Retroperitoneal Liposarcoma
Masahide Ikeguchi, Shoichi Urushibara, Ryugo Shimoda, Hiroaki Saito and Toshiro Wakatsuki
Division of Surgical Oncology, Department of Surgery, School of Medicine, Tottori University Faculty of Medicine, Yonago 683-8504,
Japan

ABSTRACTtive intent is the treatment of choice, and a negative
margin should be achieved to improve survival, even if
resection of adjacent organs is needed.4–8 But, the resultsof surgery for RL have been quite inferior to those of extremity sarcomas because of the large size at operationand difficulty in resecting the tumor due to its anatomical location. Furthermore, many patients suffer fromhigh frequency of local recurrence of tumor after such
radical and complete operation. Neoadjuvant and adjuvant treatments with chemotherapy or radiotherapy havealso not shown any consistent benefit.9, 10 This paper
shows the surgical treatment results and prognosis of RL
in a single institute of Japan.

Background

Retroperitoneal liposarcoma (RL) isa relatively rare tumor and is usually found at the advanced stage. Chemotherapy or radiotherapy for thistumor is not yet defined, and if operable, surgery is thetreatment of choice. Complete resection of tumor withwide margins including excision of other organs has
been recommended. However, many patients suffer fromdeterioration of the quality of a postoperative life. In thepresent study, we retrospectively analyzed the ideal surgical procedures for treating RL.
Methods RL patients treated at our institute between
2003 and 2013 amounted to 10. RL was primary in 5
patients and recurrent in the rest 5. We analyzed cases of
the 10 patients retrospectively.
Results Tumor resection was performed for 9 patients,
7 of whom underwent complete tumor resection. RL waswell-differentiated in 6 patients and dedifferentiated in 4.
We analyzed the overall survival of 10 patients, and therelapse free survival of the operated 9 patients. Patientswith well-differentiated RL showed better survival thanthose with dedifferentiated RL. Even the recurrent RL
was huge, complete tumor resection could be performedin the well-differentiated type, but it was difficult in thededifferentiated type.
Conclusion In the recurrent huge RL, the chance of amargin-negative resection remains low, but surgery remains the treatment of choice. Tumor resection with preserving important organs may improve patients’ qualityof postoperative life and survival.

MATERIALS AND METHODS
Between 2003 and 2013, a total of 5,590 patients visited our institute. Retroperitoneal tumors were detected
in 43 patients (0.8%). Among them, 10 patients (10/43,
23.3%) had RL. Also, malignant fibrous histiocytomas
and leiomyosarcomas were found in 10 and 7 patients,
respectively, and metastatic tumors, in 3. Recent findingson the genetic field suggest that most lesions diagnosed
as malignant fibrous histiocytomas are in fact dedifferentiated liposarcomas.11, 12 However, diagnosis of
disease known as malignant fibrous histiocytoma is not
esablished now. Thus, in the present study, we registeredonly the tumors histologically proved to be liposarcoma.
The patients’ records, operative notes, histopathological reports and imaging studies were reviewed
retrospectively. Tumor size and tumor invasion werevisualized by enhanced computed tomography and/or
magnetic resonance imaging. Clinicopathological characteristics, treatment procedures and prognoses wereanalyzed in the 10 patients.

Key words

dedifferentiation; quality of life; recurrence retroperitoneal liposarcoma; surgery
Retroperitoneal sarcomas are relatively rare. Amongthem, liposarcoma is one of the most common subtypes.
Retroperitoneal liposarcoma (RL) is classified into 5
subtypes according to the World Health Organization
Classification: well-differentiated, dedifferentiated, myxoid/round cell, pleomorphic and mixed-type.1 The peak
incidence is in the 6th decade of life2 and the incidence
is almost equal in men and women with a slight male
predominance.3
RL is often asymptomatic and considerably large
when initially diagnosed. Complete resection for cura-

RESULTS
Patients’ characteristics are indicated in Table 1. On visiting our department, 5 patients had primary lesions, andanother 5, recurrent lesions. Well-differentiated RL wasdetected in 6 patients, and dedifferentiated RL, in 4.
Corresponding author: Masahide Ikeguchi, MD
masaike@med.tottori-u.ac.jp
Received 2014 August 21
Accepted 2014 October 3
Abbreviation: RL, retroperitoneal liposarcoma

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M. Ikeguchi et al.
Table 1. Demographic details of 10 patients with retroperitoneal liposarcom (RL)

The follow-up period of patients ranged from 3 to
164 months. The mean survival time of 10 patients with
RL was 155 months, and that of 6 patients with welldifferentiated RL (157 months) was significantly longer
than that of 4 with dedifferentiated RL (135 months)(P = 0.027, Fig. 1).
Operation (resection of RL) was performed for 9 patients, but tumor resection was avoided for 1 patient because of tumor invasion to the greater psoas muscle andlumbar bone. The 9 patients had received tumor resections for the average of 3 times (range: 2–10 times). At
the initial operation, complete tumor resection was performed for 7 patients, but incomplete tumor resection for
the rest 2 due to tumor invasion to neighboring organs.
The average time interval between the initial resection
and the 2nd (relapse free survival) in the 9 patients was
54 months (range: 9–114 months). The mean relapse freesurvival of 6 patients with well-differentiated RL (64months) was longer than that of the rest 3 with dedifferentiated RL (28 months), but the difference was not
significant (P = 0.27, Fig. 2).
The following is the course of disease with the operation procedures for recent cases of 2 patients withrecurrent RL. Patient 1 was a 53-year-old female. About
10 years ago, she underwent complete resection for welldifferentiated RL at a hospital. Thereafter, huge recurrent RL took place, which was resected 1 year ago at another hospital. But, because the tumor involved the left
ureter and the left external iliac artery, the operation was
done with incomplete extraction of the tumor. According
to the rapid growth of the residual tumor, she was admitted to our institute. Abdominal enhanced computed
tomography indicated dislocation of the left ureter andthe left external iliac artery due to tumor invasion. Also,

Age at initial diagnosis, mean (range), yr
57.5 (44–73)
SexMale/female		1/9Variant
Well-differentiated		 6
Dedifferentiated		4
Myxoid/round cell		0
Pleomorphic		0
Mixed type		
0
Cases
Primary/recurrent		5/5Complete tumor resection		
7
Primary cases		 3/5Recurrent cases		 4/5

tumor invasion to the left iliopsoas muscle was observed(Fig. 3). At the time of operation, we found a huge tumor
occupying almost the whole abdominal cavity (Fig. 4).
At first, we inserted bilateral ureter stents, preserving
the bilateral common iliac arteries and veins, bilateralinternal and external iliac arteries and veins pulse bilateral ureters, and performed complete extraction of
the tumor. The extracted tumor weighed 6,500 g, theoperation time was 9.5 h and the amount of intraoperative bleeding was 2,820 mL. Patient 2 was a 65-year-old
female. She underwent incomplete resection of dedifferentiated RL at a hospital 2 years ago, because tumor
invaded to bilateral ureters and bilateral iliac arteries
and veins. But, the residual tumor enlarged graduallyand she was moved to our institute. For this patient also,bilateral ureter stents were inserted at first. Almost thewhole tumor was extracted with resection of the left internal iliac artery and vein. However, the tumor invaded
to the inferior vena cava deeply, incomplete extraction
was partly done. The extracted tumor weighed 6,000 g,
operation time was 12.5 h and the intraoperative bleed-

1

Survival rate

Survival rate

1
0.8
0.6
0.4

0.8
0.6
0.4
0.2

0.2
0

0

0

20

40

60

80

100 120 140 160 180 (mo)

0

20

40

60

80

100

120 (mo)Time after patients’ first administration
to the hospitalTime after patients’ first administration
to the hospitalFig. 2. Relapse free survival of 6 patients with well-differentiated
RL (solid line) is better than that of 3 patients with dedifferentiatedtype (dotted line), but the difference was not significant (P = 0.27).
RL, retroperitoneal liposarcoma.

Fig. 1. Overall survival of 6 patients with well-differentiated RL(solid line) is significantly better than that of 4 patients with dedifferentiated RL (dotted line, P = 0.027). RL, retroperitoneal liposarcoma.

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Retroperitoneal liposarcoma

ing amount in Patient 2 was 2,590 mL. In each of the 2patients, even though a huge tumor involved importantorgans such as ureter and external iliac artery and vein,
we could perform careful and prudent operation which

led complete tumor extraction with preserving importantorgans.

Fig. 3. Abdominal enhanced computed tomography indicatesdislocation of the left ureter and the left external iliac artery due totumor invasion.

Fig. 4. The huge tumor occupies the whole abdominal cavity.

Left ureter
Left common ileac arteryLeft psoas muscle
Left external ileac artery

Fig. 5. Complete resection of tumor with preserving importantorgans was performed.

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DISCUSSION
Since RL has no characteristic symptom, patients often
enter hospital with a very huge RL. Complete resectionof RL with a surrounding margin of normal tissue is the
only way to cure the patients, because the effectivenessof radiotherapy and chemotherapy for RL has not been
established. A few retrospective studies reported thatpatients who had received adjuvant radiotherapy had asignificant improvement in local failure free survival
compared to patients who underwent surgery alone.13,
14
On the other hand, Ballo et al.15 found no benefits
from radiotherapy for RL. Moreover, they emphasizedthat a significant amount of toxicities of radiotherapy
causes neuropathy, hydronephrosis, ureteral fistula andbowel obstruction. Thus, we have to consider that radiotherapy to the retroperitoneum is challenging becauseof the large field size and presence of important visceralstructures like the kidney, liver, bowels and spinal cord.
Also, few retrospective and prospective studies indicatedthat neoadjuvant or adjuvant chemotherapy showed thesurvival benefit of patients with RL. Moreover, they
concluded that chemotherapy worsened the performancestatus of the patients.16, 17
To achieve a negative margin depends on the relation of tumor to major vascular structures and to invasion of adjacent visceral organs. Complete resection
rates in several series for primary RL vary from 43% to95%.18–21 The rate will be worse in patients with recurrent huge RL. In our series, the complete resection rateof primary RL was 78%. To achieve a negative margin,
Kumar et al.22 recommended combined resection of one
or more organs abutting the tumor such as kidney, colon,
adrenals, spleen and pancreas rather than peeling off
the organ from the tumor. But we know that many RL
patients who underwent combined resection suffer fromconditions lacking important organs. Moreover, huge RL
often involves inferior vena cava, abdominal aorta, common ileac artery or vein, or bilateral ureters. For suchpatients, peeling off technique should be recommended
to preserve the important organs.
The well-differentiated liposarcomas grow slowly,
but dedifferentiated sarcomas grow faster and have ahigher ability to metastasize than well-differentiatedliposarcomas. We found that well-differentiated RL
had better outcomes in terms of recurrence, rate of metastasis and overall survival than dedifferentiated RL.
Moreover, considerable attention is paid to the observation that well-differentiated liposarcoma may convert todedifferentiated liposarcoma after one or more recur-M. Ikeguchi et al.

rences.23, 24 In the present study, we found that dedifferentiated RL more hardly invaded to neighboring organs(aorta, vena cava or ureter) than well-differentiated RL.
So, the peeling off operation was more difficult in dedifferentiated RL.
Local recurrence of RL after surgery is frequent andthe rate was reported from 50% to 85%.25, 26 RL recurs
in a huge form, but surgery remains the treatment ofchoice. Although the chance of a margin-negative resection remains low, adequate resection is associated with
an improved survival and hence surgery is preferred forrecurrent disease. Also, we can consider adjuvant radiotherapy to improve the relapse free survival of patientswith recurrent RL. Radiotherapy to the retroperitoneumis challenging and the radiation dose should be in minimum to avoid the risk of radiation injury.

12 Coindre JM, Hostein I, Maire G, Derré J, Guillou L, Leroux
A, et al. Inflammatory malignant fibrous histiocytomas anddedifferentiated liposarcomas: histological review, genomic
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13 Stoeckle E, Coindre JM, Bonvalot S, Kantor G, Terrier P,
Bonichon F, et al.; French Federation of Cancer Centers
Sarcoma Group. Prognostic factors in retroperitoneal sarcoma: a multivariate analysis of a series of 165 patients of theFrench Cancer Center Federation Sarcoma Group. Cancer.
2001;92:359-68. PMID: 11466691.
14 Sampath S, Hitchcock YJ, Shrieve DC, Randall RL,
Schultheiss TE, Wong JY. Radiotherapy and extent of surgicalresection in retroperitoneal soft tissue sarcoma: Multi-institutional analysis of 261 patients. J Surg Oncol. 2010;101:345-50.
PMID: 20119974.
15 Ballo MT, Zagars GK, Pollock RE, Benjamin RS, Feig BW,
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Biol Phys. 2007;67:158-63. PMID: 17084545.
16 Meric F, Hess KR, Varma DG, Hunt KK, Pisters PW, Milas
KM, et al. Radiographic response to neo-adjuvant chemotherapy is a predictor of local control and survival in soft tissue
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17 Pervaiz N, Colterjohn N, Farrokhyar F, Tozer R, FigueredoA, Ghert M. A systematic meta-analysis of randomized controlled trials of adjuvant chemotherapy for localized resectable soft-tissue sarcoma. Cancer. 2008;113:573-81. PMID:
18521899.
18 Catton CN, O’Sullivan B, Kotwall C, Cummings B, Hao Y,
Fornasier V. Outcome and prognosis in retroperitoneal soft
tissue sarcoma. Int J Radiat Oncol Biol Physics. 1994;29:100510. PMID: 8083069.
19 Karakousis CP, Kontzoglou K, Driscoll DL. Resectability ofretroperitoneal sarcoma: a matter of surgical technique? Eur J
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The authors declare no conflict of interest.
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