Surgical excision of a giant retroperitoneal liposarcoma with renal cell carcinoma: A case report of the largest retroperitoneal sarcoma

Abstract

Introduction

Retroperitoneal liposarcomas are rare malignant tumors known for their slow growth and challenging management, particularly due to their substantial size upon diagnosis. This case report highlights a remarkable instance of a massive retroperitoneal sarcoma concomitant with synchronous renal cell carcinoma.

Case presentation

We report a 57-year-old male patient with a huge abdominal mass hampering his daily activities and on further investigation, CECT abdomen and pelvis revealed a large Retroperitoneal Scarcoma (RPS) occupying his entire abdominal cavity displacing the visceral organs. In accordance with the final decision of the multi-disciplinary team meeting, he was subjected for surgery and the tumor was excised enbloc. He is kept under surveillance.

Discussion

Surgery remains the main modality of treatment for RPS. Hence careful preoperative surgical planning and execution with meticulous dissection aids in achieving a good clinical outcome and to reduce recurrence in future.

Conclusion

Despite the huge size of the tumor, surgical intervention remains the primary treatment option whenever feasible, often complemented by additional therapeutic approaches.

Highlights

• •Retroperitoneal liposarcomas (RPS) are slow growing rare tumors with late presentation in advanced stage.
• •Surgical intervention becomes challenging in view of huge size and proximity with vital structures in the retroperitoneum.
• •Preoperative surgical planning with the aid of imaging modalities and meticulous dissection plays a key role in achieving enbloc resection.
• •Multi-disciplinary team approach should be considered to emphasis patient safety and to overcome the therapeutic challenge.

1. Introduction

Retroperitoneal sarcoma (RPS) is an uncommon tumor, occurring in less than one case per 100,000 individuals annually, and comprising approximately 10–15 % of all soft tissue tumors [1,2]. Due to its retroperitoneal location and slow growth rate, patients frequently present at advanced stages with sizable retroperitoneal masses, making surgical intervention highly challenging for both the surgeon and the patient. Notably, this case represents the largest reported retroperitoneal sarcoma in terms of dimensions (66x38x37cm) and weight (30.5 kg) within the published literature.

2. Case report

A 57-year-old Indian male patient presented to our surgical oncology outpatient department (OPD) on December 27th, 2022, with a gradually enlarging abdomen over the past 18–24 months. According to the patient, he had perceived weight gain despite a decrease in his actual dietary intake. He also experienced difficulty walking and performing daily activities due to the abdominal distension. For the past 6 to 8 months, he had been unable to lie supine for an extended period and resorted to sleeping in a lateral position. Apart from a surgery for an inguinal hernia performed four years ago, the patient had no other significant medical history or comorbidities. Upon physical examination, the patient appeared well-built with an Eastern Cooperative Oncology Group (ECOG) performance status of 2. Abdominal examination revealed a large, poorly defined mass with side-to-side mobility but limited vertical movement. A contrast-enhanced CT scan was conducted, which revealed a large, solid mass with fatty density encompassing almost the entire abdomino-pelvic cavity, causing displacement of the intra-abdominal organs superiorly (Fig. 1, Fig. 2). Multiple septations and some areas of calcification were observed within the mass. Additionally, a heterogeneously enhancing lesion measuring 5.2 × 4.7 cm was detected in the mid-polar region of the right kidney. To assess renal function, a DTPA scan was performed, revealing a glomerular filtration rate (GFR) of 108 ml/min, with equal contribution from both kidneys.

Fig. 1.

Axial section of CECT Abdomen image. Fat dense solid mass with septations and mid polar lesion in right kidney (blue arrow). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Fig. 2.

Sagittal section of CECT Abdomen. Superiorly displaced bowel loops because of the huge RPS.

The presented case was thoroughly reviewed and discussed in our multidisciplinary meeting, leading to a unanimous decision to proceed with surgical intervention. Considering the diagnostic imaging findings, a biopsy was deemed unnecessary as the features were indicative of a substantial liposarcoma accompanied by right renal cell carcinoma. Given the circumstances, surgery emerged as the sole therapeutic option available for the patient.

The case was extensively reviewed and deliberated with our anesthesia team to address potential concerns. The primary focus of the anesthesia team was the risk associated with prolonged supine positioning, which could lead to compression of major vessels, resulting in hemodynamic instability. Additionally, the size of the tumor and its anatomical relationships raised concerns about the potential for significant blood loss during the procedure. To mitigate these concerns, a decision was reached to position the patient in a supine position, while employing two wedge pillows to elevate the right side slightly. In anticipation of potential massive blood loss, our blood bank team was promptly informed, and six units of blood and blood components were prepared in advance.

The patient was provided with a comprehensive explanation regarding his medical condition, emphasizing that surgery is the sole curative option available in his case. Detailed discussions were held to ensure the patient's understanding of the surgical approach and the associated intraoperative risks resulting from the substantial size of the tumor and its proximity to major abdominal vessels. Additionally, the necessity for en-bloc excision of the right kidney alongside the retroperitoneal mass was thoroughly discussed and clarified to the patient. Following a thorough discussion and obtaining written informed consent, the patient was subsequently taken for surgery.

The surgery was performed by the author who is the chief of the Sarcoma unit. The procedure commenced with a midline incision extending from the xiphisternum to the pubic symphysis. Placement of Thompson retractors was attempted; however, due to the limited intra-abdominal space, they provided minimal assistance. The tumor was gently pushed downward to facilitate access, and the procedure began by identifying the Duodenojejunal (DJ) flexure. The DJ flexure was meticulously freed, allowing entry into the lesser sac, which proved more challenging than anticipated due to fused omental layers. The tumor was dissected away from the anterior surface of the pancreas and duodenum. Subsequently, the dissection followed the course of the small bowel and its mesentery distal to the DJ flexure. While the transverse mesocolon and ascending colon were mobilized forward, they were found to be uninvolved, and a well-defined bursectomy plane was identified. Once the tumor was dissected free from the small bowel, colon, and pancreatic capsule, attention shifted to the subhepatic area and Morrison's pouch. Careful dissection revealed the right renal vein and renal artery. Notably, this case presented with two renal arteries, with the renal vein coursing between them. After ligating the renal vessels, the kidney, along with Gerota's fascia and a sleeve of psoas muscle, was elevated. The dissection continued along the inferior vena cava (IVC) and aorta. Throughout the surgery, retraction of the tumor posed a persistent challenge. One assistant provided external pressure, while the other maintained suspension of the tumor, enabling the operating surgeon to proceed. Dissection continued until both common iliac arteries and their subsequent branching into external and internal iliac arteries were exposed. The inferior mesenteric artery and vein were ligated at their origin, and the tumor was carefully delivered outside the abdomen. The tumor exhibited multiple small feeder vessels originating from the renal artery, aorta, and inferior mesenteric artery, all of which were meticulously ligated. Although the estimated intraoperative blood loss was 400 ml, the volume of the tumor was taken into consideration when administering intravenous fluids and blood products. After the tumor was removed, it was rolled onto a sheet and lifted by two individuals for weighing, which yielded a measurement of 30.54 kg (Fig. 3). Following tumor excision, the DJ flexure was repositioned anatomically, and the ascending colon and hepatic flexure were attached to the retroperitoneum (Fig. 4). No abdominoplasty was performed for abdominal wall laxity; instead, the patient was advised to use an abdominal binder during the postoperative period. The duration of the surgery was approximately 6 h, during which the patient remained hemodynamically stable. Postoperative recovery was uneventful, and the patient was discharged in stable condition on the 8th postoperative day, resuming a full diet. The specimen was grossed in the pathology department and measured 66x38x37 cm. Histopathological examination revealed a well-differentiated liposarcoma (pT4N0) concomitant with synchronous clear cell renal carcinoma on the right side (pT1bN0). The patient is currently being closely monitored during follow-up and has been leading a normal life without any complications thus far.

Fig. 3.

Resected specimen on weighing scale. Enbloc resected giant retroperitoneal liposarcoma with right renal cell carcinoma weighing 30.54 kg.

Fig. 4.

Post RPS excision retroperitoneal bed. Arrowhead points the right side cranial end of the patient.

A written informed consent was obtained from the patient for publication of this case report and accompanying images. The case report has been constructed adhering to the SCARE criteria [3].

3. Discussion

Liposarcoma represents the predominant histological variant among retroperitoneal sarcomas (RPS), accounting for over 50 % of cases [4]. It is further classified into four types based on morphological features and cytogenetic aberrations: well-differentiated, dedifferentiated, myxoid/round cell, and pleomorphic [5]. The natural history and recurrence patterns of RPS are influenced by various factors, including histology, histological grade, size, resectability, nodal disease, and distant metastases [6,7]. Approximately 10 % of RPS cases demonstrate a propensity for metastasis, with the liver and lungs being the most common sites [6]. The median age of presentation for retroperitoneal liposarcoma is 56 years, with an equal distribution between genders. Due to their slow-growing nature, patients often present late when the tumor has already reached a significant size, causing compression symptoms on the gastrointestinal tract and urinary system [8].

Contrast-enhanced CT scan is the imaging modality of choice for diagnosing RPS. In cases of resectable RPS, biopsy is not typically performed based on imaging alone. However, for cases with borderline resectability undergoing neoadjuvant therapy, a core needle biopsy is necessary to ascertain the histology. Although the risk of needle tract metastasis after core needle biopsy for retroperitoneal sarcoma is very low, it is not zero [9].

Surgery remains the cornerstone of treatment for RPS, aiming to achieve negative margins through en bloc excision of the tumor along with involved structures. Retroperitoneal sarcomas are closely related to vital structures such as the IVC, aorta, kidneys, small bowel, and large bowel, making wide excision with a margin of normal tissue extremely challenging. In our case, we performed en bloc resection of the tumor along with the right kidney and a portion of the right psoas muscle. Locoregional recurrence rates for retroperitoneal sarcomas range from 28 % to 48 % [10]. Extended resections, known as “compartment excision,” have shown improved locoregional control without significant overall survival benefit [10]. Well-differentiated retroperitoneal sarcomas have an excellent prognosis, with 5-year survival rates exceeding 90 %.

The role of neoadjuvant treatment in RPS remains debatable. The addition of neoadjuvant radiation therapy in operable RPS has not demonstrated any survival benefit, as evidenced by the recently published STRASS trial [11]. Adjuvant radiation therapy has shown efficacy in delaying local recurrence, but it does not impact overall survival, as indicated by historical case series [12,13]. Evidence supporting adjuvant radiation therapy is limited, and its use in postoperative settings for large RPS is uncommon in modern practice. Chemotherapy and tyrosine kinase inhibitors play a limited role and are primarily utilized in the treatment of metastatic RPS. Most trials evaluating adjuvant chemotherapy have focused on extremity sarcomas, and the current evidence is not robust enough to recommend adjuvant chemotherapy for RPS. Furthermore, neoadjuvant chemotherapy has failed to demonstrate any survival benefit, and concerns have been raised regarding its potential to delay surgical excision, which currently remains the only curative modality.

4. Conclusion

Retroperitoneal sarcomas present a significant therapeutic challenge due to the intricate surgical procedures required for their excision and their limited response to chemotherapy and radiation. It is crucial to thoroughly evaluate the radiological features of these tumors to determine their potential for resection. Despite the inherent difficulties associated with their management, a comprehensive surgical approach remains the key to successful treatment of retroperitoneal sarcomas.

Ethics approval

The Institutional Research Ethics Committee has confirmed that no ethical approval is required.

Research registration

Not required for this case report.

Funding

No funds, grants, or other support was received.

Declaration of competing interest

The authors declare no conflicts of interest.