Abstract
Primary retroperitoneal sarcomas (RPS) are rare, with leiomyosarcoma (LMS) being the second most common subtype. While open surgery is the standard of care, total laparoscopic resection for large RPS remains technically challenging and infrequently reported. Herein, we present a rare case of a 60-year-old woman who presented with a 6-month history of dull abdominal pain. Computed tomography revealed a large 10 cm retroperitoneal mass initially mimicking a duodenal gastrointestinal stromal tumour. The patient underwent a successful totally laparoscopic en bloc R0 resection with uneventful recovery. Histopathology and immunohistochemistry confirmed LMS (Actin and Desmin positive; CD117, CD34, DOG1, β-catenin, and S100 negative). Genetic analysis identified a rare TP53 G105R mutation (c.313G > C). Conclusion: Total laparoscopic R0 resection is a safe and feasible option for large LMS when performed by experienced surgical teams. Identifying rare molecular profiles provides deeper insights into the biological behaviour and personalized management of this rare disease.
Introduction
Primary retroperitoneal sarcomas (RPS) are rare malignancies, accounting for <1% of all adult solid tumours [1–3]. Leiomyosarcoma (LMS) is the second most frequent histological subtype, accounting for ~20%–30% of cases. LMS often originates from retroperitoneal vascular structures and is characterized by a high risk of distant metastasis [3–5]. Due to silent progression in the retroperitoneal space, these tumours often reach a massive size before diagnosis [1, 2, 6].
Complete en bloc surgical resection with negative margins remains the cornerstone of curative treatment and the primary determinant of long-term survival [1, 5, 7]. While open surgery is the standard approach for large tumours, minimally invasive surgery offers benefits such as faster recovery and reduced blood loss [1, 8, 9]. However, its application in RPS is technically restricted by deep anatomical locations and proximity to major neurovascular structure [5, 8, 9]. The available literature indicates that reported totally laparoscopic resections have predominantly involved tumours measuring 7–11 cm, suggesting that laparoscopic resection is feasible in carefully selected patients [5, 8, 10].
Recent advancements emphasize the role of molecular profiling in understanding sarcoma behaviour. While strong positivity for Actin and Desmin serves as the diagnostic hallmark for LMS, the presence of TP53 mutations is associated with increased genomic instability and aggression [2, 3]. We report a unique case of a large LMS successfully treated via totally laparoscopic R0 resection, harbouring a rare TP53 mutation.
Case report
A 60-year-old female presented with a 6-month history of persistent dull pain in the right flank radiating to the back, accompanied by decreased appetite. Her medical history was significant only for hypertension, with no prior abdominal surgeries or a family history of malignancy. On physical examination, the patient’s vital signs were stable. Abdominal palpation revealed a poorly mobile, non-tender mass in the right upper quadrant and flank.
Laboratory investigations, including complete blood count, liver and renal function tests, and tumour markers (CEA: 1.29 ng/ml), were all within normal limits. Chest X-ray, upper gastrointestinal endoscopy, and colonoscopy were unremarkable. Initial abdominal ultrasound identified a mixed-echoic retroperitoneal mass near the right kidney. Contrast-enhanced computed tomography (CT) scan subsequently revealed a large, solid, well-demarcated mass in the retroperitoneum, measuring ~6 × 7 × 10 cm. The tumour was located below the D2 segment of the duodenum (Figs 1 and 2). The initial radiologic differential diagnosis suggested a mesenteric tumour or a gastrointestinal stromal tumour (GIST) originating from the D2 segment of the duodenum.
Contrast-enhanced abdominal CT scan showing a retroperitoneal mass (arrow) measuring 6 × 7 × 10 cm on the sagittal view.
Axial contrast-enhanced abdominal CT scan showing a retroperitoneal mass (arrow) adjacent to the second portion of the duodenum (D2).
Based on the clinical and radiological findings, the patient was diagnosed with an intra-abdominal/retroperitoneal tumour, with duodenal GIST as the leading differential diagnosis. Following a multidisciplinary board discussion, a totally laparoscopic en bloc resection was planned. Intraoperatively, a large encapsulated mass was identified in the retroperitoneal space (Fig. 3). Under magnified vision, the tumour was meticulously dissected from the duodenum, right kidney, and major vascular structures, showing no signs of direct invasion. Small feeding vessels were controlled using laparoscopic shears (Figs 4 and 5). The specimen was removed intact through a small vertical extension of the umbilical incision to maintain oncological integrity. The total operative time was 120 minutes with a minimal estimated blood loss of 50 ml. The postoperative course was uneventful, and the patient was discharged on postoperative day 4.
Intraoperative image demonstrating the retroperitoneal tumor (RT) adjacent to the second portion (D2) of the duodenum (DD).
Intraoperative view showing the retroperitoneal tumor (RT) after mobilization and dissection from the surrounding structures, including the duodenum (DD), the ileocolic vascular pedicle (IVP), and superior mesenteric vein (SMV).
Intraoperative image after complete tumor resection, demonstrating the preserved right kidney (RK), right ureter (RU), duodenum (DD), ileocolic vascular pedicle (IVP), and superior mesenteric vein (SMV).
Macroscopic examination of the specimen revealed a large, firm, white-solid mass measuring ~6 × 7 × 10 cm (Fig. 6). Microscopic analysis revealed a poorly differentiated spindle cell sarcoma composed of fascicles and whorls. Based on the histopathological findings alone, GIST could not be excluded. Immunohistochemistry demonstrated positive staining for ACTIN and DESMIN, whereas CD117, CD34, DOG1, β-catenin, and S100 were negative, confirming the diagnosis of LMS (Fig. 7). Subsequent genetic analysis using next-generation sequencing identified a rare TP53 G105R mutation (c.313G > C, exon 4) with a variant allele frequency of 46.6%. No clinically significant mutations were found in KIT, PDGFRA, or NTRK genes (Fig. 8). At the 3-month follow-up, repeat CT imaging showed no signs of local recurrence.
Gross specimen showing the retroperitoneal tumour after en bloc resection with an intact capsule.
Immunohistochemical staining showing negative expression of CD117, CD34, DOG1, β-catenin, and S100, with positive staining for ACTIN and DESMIN.
Results of genetic analysis demonstrating the presence of a G105R mutation in the TP53 gene.
Discussion
Retroperitoneal LMS is an uncommon subtype of retroperitoneal sarcoma, representing ~20%–30% of cases [2, 4, 11]. Because the retroperitoneal space is expansive and allows for silent tumour growth, these tumours often reach a massive size—frequently exceeding a median diameter of 15–20 cm—before clinical detection [1, 7, 12]. Our case, involving a 10-cm large mass, exemplifies this characteristic silent progression.
Diagnosing RPS remains challenging as clinical symptoms are often nonspecific. Cross-sectional imaging, particularly contrast-enhanced CT, is the gold standard for assessing tumour size and relationship to adjacent structures [4, 12–14]. However, imaging alone can sometimes misidentify RPS as other spindle-cell tumours, such as GIST [4, 12]. In our patient, the tumour’s proximity to the duodenum initially led to a suspected diagnosis of a duodenal GIST. This diagnostic pitfall highlights the necessity of histopathological and immunohistochemical confirmation. The strong positivity for Actin and Desmin in our case was pivotal, as these markers are recognized diagnostic hallmarks that distinguish LMS from other mimics [3, 7, 12].
Complete en bloc surgical resection with R0/R1 margins remains the cornerstone of curative treatment and the primary determinant of long-term survival [1, 11]. Although open surgery has traditionally been considered the standard approach for large RPS, minimally invasive surgery is emerging as a feasible option in selected cases [1, 15]. Most reported laparoscopic resections have involved tumours measuring ~7–11 cm [8, 10]. Our successful totally laparoscopic R0 resection of a nearly 10-cm mass is comparable to these largest documented cases, further demonstrating the technical feasibility of this approach for significant retroperitoneal tumours when performed by experienced surgeons. Magnified laparoscopic visualization facilitated meticulous dissection from the duodenum and major vascular structures, contributing to minimal blood loss, rapid recovery, and discharge on postoperative day 4.
A unique feature of this report is the identification of a rare TP53 G105R mutation. TP53 is a critical tumour suppressor, and its mutation in LMS is often associated with increased genomic instability and a more aggressive clinical course [2]. Although R0 resection remains the cornerstone of curative treatment, LMS carries a high risk of distant metastasis, with rates of up to 55%–56% at 5 years [3, 11]. Therefore, the presence of a TP53 mutation may provide additional insights into tumor biology and support personalized risk assessment and long-term surveillance.
Conclusion
Totally laparoscopic R0 resection is a safe and feasible approach for large retroperitoneal LMS, offering rapid recovery without compromising oncological principles. Moreover, identifying rare genomic alterations like the TP53 mutation provides valuable biological insights for personalized risk assessment and intensified long-term surveillance.
Acknowledgements
We thank you for the support from Can Tho University of Medicine and Pharmacy.
Conflicts of interest
The authors declare no conflict of interest.
Funding
This research received no external funding.
Data availability
Data are contained within the article. Data sharing does not apply to this article.
Informed consent statement
Informed consent was obtained from all subjects involved in the study.
