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Radiol Case Rep
Radiol Case Rep
Radiology Case Reports
1930-0433
Elsevier

S1930-0433(24)00728-3
10.1016/j.radcr.2024.07.142
Case Report
Synchronous retroperitoneal liposarcoma and gastric adenocarcinoma: A rare case report
Essetti Sara s.essetti@gmail.com
a⁎
Imrani Kaoutar a
Faraj Chaymae a
Chehrastane Rachida a
Ez-zaky Sara a
Billah Nabil Moatassim a
Nassar Ittimade a
Babana Amina Alaoui b
Touhami Youssef Ouazzani b
El Malki Hadj Omar b
Ifrine Lahcen b
Belkouchi Abdelkader b
Belkouchi Omar b
El Mohtarim Rihane c
Sassi Samia c
Derqaoui Sabrine c
Bernoussi Zakiya c
a Central Radiology Department, Ibn Sina University Hospital Center, Mohamed V University of Rabat, Morocco
b Department of Surgery A, Ibn Sina University Hospital, Mohammed V University, Rabat, Morocco
c Department of Pathology, Ibn Sina University Hospital, Mohammed V University, Rabat, Morocco
⁎ Corresponding author. s.essetti@gmail.com
23 8 2024
11 2024
23 8 2024
19 11 51585163
18 7 2024
23 7 2024
24 7 2024
© 2024 The Authors. Published by Elsevier Inc. on behalf of University of Washington.
2024

https://creativecommons.org/licenses/by-nc-nd/4.0/ This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Multiple primary malignancies can occur as either synchronous or metachronous tumors, particularly in adults. Retroperitoneal liposarcoma is a rare malignancy arising from adipose tissue, while gastric adenocarcinoma is one of the most common neoplasms worldwide. The simultaneous occurrence of these 2 malignancies is extremely rare, with only 1 case reported worldwide. Here, we present the case of a 52-year-old man diagnosed with both retroperitoneal liposarcoma and gastric adenocarcinoma, marking the second reported case in the world.

Keywords

Retroperitoneal liposarcoma
Gastric adenocarcinoma
Soft-tissue sarcoma
CT
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pmcIntroduction

Synchronous primary malignancies are rare and present significant diagnostic and therapeutic challenges. Retroperitoneal liposarcoma is an uncommon malignant tumor, representing about 15% of all soft tissue sarcomas [1]. Soft-tissue sarcomas comprise a diverse group of malignancies, constituting less than 1% of all adult malignant neoplasms [2]. These tumors are characterized by varying molecular events and epidemiological profiles, which categorize them into different subtypes.

On the other hand, gastric cancer is the fourth most commonly diagnosed cancer and the second leading cause of cancer-related deaths worldwide [3]. Adenocarcinoma is the predominant histological type of gastric cancer, contributing to the majority of cases [4]. The prognosis of gastric cancer remains poor, particularly in advanced stages, despite advances in surgical techniques and chemotherapeutic regimens.

The simultaneous occurrence of these 2 malignancies is exceptionally rare, with only one previously reported case worldwide [5]. This rarity poses significant challenges in both diagnosis and management, as treatment protocols for each malignancy may conflict or complicate the overall therapeutic approach.

In this report, we present the case of a patient diagnosed with synchronous retroperitoneal liposarcoma and gastric adenocarcinoma, discussing the clinical presentation, diagnostic process, treatment strategies, and the outcomes.

Case report

A 52-year-old man with no significant medical history presented to the Department of Surgery at our University Hospital with a gradually enlarging abdomen over the past 6 months. The patient also reported intermittent constipation and decreased appetite. Physical examination revealed a nontender, distended abdomen with a palpable mass extending from the left hypochondrium to the pelvic region. Routine blood tests showed isolated anemia with a hemoglobin level of 9.

A contrast-enhanced CT scan of the abdomen revealed a large, heterogeneous, well-defined mass predominantly composed of fat measuring 27 × 25 × 19 cm. The mass displaces the descending colon, sigmoid colon, and small bowel loops. Internally, the mass shows several thick septa and nodular soft tissue components with areas of calcification (Figs. 1A and B), suggestive of liposarcoma. Furthermore, at the limit of an examination performed without gastric distension, a circumferential and regular gastric wall thickening was noted, along with multiple lymphadenopathies of the lesser curvature of the stomach (Fig. 1C).Fig. 1 Contrast-enhanced abdominal CT on the portal phase revealed a large, heterogeneous abdominopelvic mass (white arrow) predominantly composed of fatty tissue. Internally, the mass showed several thick septa (red arrow) and nodular soft tissue components (asterisks) with areas of calcification (blue arrow), consistent with liposarcoma. Additionally, there was noted circumferential and regular thickening of the gastric wall (orange arrows), along with multiple lymphadenopathies affecting the lesser curvature of the stomach (yellow arrow).

Fig 1:

The patient was scheduled for an esophagogastroduodenoscopy but presented with severe hematemesis, necessitating emergency surgery. Surgical exploration revealed a tumoral mass at the lesser curvature of the stomach with signs of active bleeding, along with a large, lobulated retroperitoneal mass. The patient subsequently underwent a total gastrectomy (Fig. 2A) with esophagojejunal anastomosis, omentectomy, and lymph node dissection, as well as an en bloc resection of the retroperitoneal mass (Fig. 2B). The mass was 33 × 27 × 15 cm in size. The postoperative course was uneventful and the patient made a good recovery.Fig. 2 Postoperative illustrations showing the total gastrectomy specimen with the tumoral mass at the lesser curvature of the stomach (A) and the retroperitoneal mass (B).

Fig 2:

Histopathological examination of the gastric tumor revealed a poorly differentiated tubular adenocarcinoma classified as pT3N3b (Fig. 3), while the retroperitoneal mass was identified as a well-differentiated liposarcoma (Fig. 4).Fig. 3 Histologic staining photomicrographs show a poorly differentiated adenocarcinoma (A: H-E stain: original magnification x 40), The architecture is composed of cords and trabeculae (B, C: H-E stain: original magnification x100 and 200), tumor cells show major cytonuclear atypia (D: H-E stain: original magnification x 400).

Fig 3:

Fig. 4 Histologic staining photomicrographs show a well differentiated liposarcoma associating 3 territories; a lipoma-like zone (A, B: H-E stain: original magnification x 40 and 400), inflammatory zone (B: H-E stain: original magnification x 100) and sclerosing zone (D: H-E stain: original magnification x 100).

Fig 4:

The subsequent metastatic work-up did not reveal any metastatic lesions. A multidisciplinary team recommended adjuvant chemotherapy, which the patient successfully completed with a favorable outcome.

Discussion

Soft tissue sarcomas are a group of neoplasms that can arise from various tissues throughout the body, representing less than 1% of all malignancies [2]. Approximately 15% of soft tissue sarcoma cases involve the retroperitoneum, with liposarcomas accounting for nearly 40% of these retroperitoneal sarcomas [6].

Retroperitoneal liposarcoma occurs in fewer than 1 case per 100,000 individuals annually [7]. The average age at presentation is 54 years, with an equal with an equal distribution between males and females [1].

Most soft tissue sarcomas, including retroperitoneal liposarcoma, have no clearly identified cause. However, the European Society for medical oncology (ESMO) has identified several predisposing factors for retroperitoneal liposarcoma, such as genetic abnormalities (Neurofibromatosis type 1, Li-Fraumeni syndrome, FAP/Gardner syndrome), exposure to ionizing radiation (especially in children undergoing multiple computed tomography scans), and diabetes mellitus [8].

Histologically, liposarcomas can be classified into 4 main types based on their morphological features and genetic abnormalities: well-differentiated, dedifferentiated, myxoid/round cell, and pleomorphic [9]. According to the World Health Organization (WHO) classification system, well-differentiated liposarcomas are considered intermediate-grade tumors, while the other subtypes are considered high-grade tumors [10].

The clinical presentation of retroperitoneal liposarcoma varies widely and depends on the tumor's size, location, and extent of involvement of adjacent structures. In the early stages, the tumor is asymptomatic and often discovered incidentally. However, patients may present with a palpable abdominal mass or a sensation of abdominal fullness. This mass is typically unilateral and can gradually increase in size [11]. In advanced stages of the disease, patients may develop gastrointestinal, urinary, or neurological symptoms due to compression or invasion of adjacent structures.

The preferred diagnostic methods for evaluating retroperitoneal tumors, including retroperitoneal liposarcoma, are contrast-enhanced CT scans and MRI of the abdomen and pelvis [12]. These imaging techniques provide detailed information about the tumor's anatomical location, size, and organ of origin. Additionally, they help assess the tumor's relationship to adjacent visceral and neurovascular structures and identify any associated lesions. Liposarcoma has a characteristic appearance on CT and MRI, typically presenting as a large encapsulated mass containing variable amounts of fatty and soft tissue components that may enhance after contrast material administration [13]. Thick septa and calcifications may also be observed.

On imaging, well-differentiated liposarcoma primarily consists of fatty tissue but may also show thick septa and nodular soft-tissue elements smaller than 1 cm [14]. The presence of a focal nodular soft-tissue element larger than 1 cm is suggestive of dedifferentiation. Myxoid liposarcoma has a distinct appearance on MRI, typically showing low signal intensity on T1-weighted sequences and high signal intensity on T2-weighted sequences due to its high water content [15]. Pleomorphic liposarcoma (LPS) generally appears as a well-defined mass with minimal or no fat content, often accompanied by intralesional hemorrhage and necrosis [15].

Several pathologies are included in the differential diagnosis of retroperitoneal liposarcoma:• Leiomyosarcoma: Characterized by areas of cystic degeneration and necrosis, and it does not contain fat [16].

• Retroperitoneal Malignant Fibrous Histiocytoma: This is the third most common histological type among malignant tumors of retroperitoneal origin, after liposarcoma and leiomyosarcoma. On imaging, it typically manifests as a well-defined, smooth, or lobular soft tissue mass without fat content.

• Retroperitoneal Lipomatosis: This condition is characterized by the accumulation of fatty tissue in the retroperitoneum. It can be distinguished from retroperitoneal liposarcoma as it does not cause a mass effect or displace retroperitoneal structures [17].

To confirm the diagnosis of retroperitoneal liposarcoma, a percutaneous core needle biopsy may be performed. Histologically, liposarcoma displays hyperchromatic single cells, broad cellular septa, and multivacuolated lipoblasts [18]. However, a biopsy may not always be necessary, especially when radiologic features strongly suggest the diagnosis [19].

A combined case series study of sarcoma patients revealed an increased risk of second malignancy in individuals with well-differentiated and dedifferentiated liposarcoma, especially those diagnosed under 50 years of age [20]. Among 312 consecutive patients diagnosed with these types of liposarcoma, 26 (8.3%) developed a second primary cancer either concurrently or within 2 years of diagnosis. These secondary cancers affected a variety of tissues and organs (prostate, kidney, lung, thyroid, sigmoid, gallbladder…). Notably, gastric adenocarcinoma was not reported in any patient in this study.

In another study that analyzed the risk of multiple primary tumors in 818 patients previously diagnosed with soft tissue sarcoma, 203 additional malignancies developed in 164 (20%) patients, with a median occurrence of 10 years before and 4 years after the sarcoma diagnosis [21].

The simultaneous occurrence of retroperitoneal liposarcoma and gastric adenocarcinoma is exceptionally rare, with only 1 case previously reported worldwide, documented in Japan, where the patient's outcome resulted in death [5]. This patient presented with differentiated retroperitoneal liposarcoma and poorly differentiated invasive adenocarcinoma.

On CT or MRI, gastric carcinomas can present as a focal area of mural thickening with or without ulceration, as a polypoid lesion, or as generalized mural thickening. Lesions in the antrum, body, and fundus each account for approximately 30% of all gastric carcinomas, while the remaining 10% involve the entire stomach [22].

Surgery remains the primary treatment for RPS, with the goal of achieving negative margins by performing an en bloc excision of the tumor along with any involved structures [7]. However, complete resection of the tumor is often challenging due to its large size at diagnosis and involvement with neighboring organs and critical structures.

The coexistence of retroperitoneal liposarcoma and gastric adenocarcinoma poses significant challenges due to the complexity of managing 2 distinct malignancies simultaneously. A multidisciplinary approach involving surgical oncologists, medical oncologists, radiologists, and pathologists is essential for optimal patient management. Individualized treatment plans should consider the stage and behavior of both tumors, the patient's overall health, and preferences.

Conclusion

The synchronous occurrence of retroperitoneal liposarcoma and gastric adenocarcinoma is an extremely rare phenomenon, presenting significant diagnostic and therapeutic challenges. Continued documentation and analysis of such rare cases are essential to improve understanding and develop evidence-based guidelines for optimal patient management. Future research should focus on the genetic and molecular underpinnings of synchronous malignancies to enhance early detection, prognostication, and targeted therapeutic strategies.

Patient consent

Written informed consent for the publication of this case report was obtained from the patient.

Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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