Alterations in portal vein confluence during gastric cancer surgery: two case reports

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Korean Journal of Clinical Oncology. 2025;21(1):40-46

Publication date (electronic) : 2025 April 30

doi : https://doi.org/10.14216/kjco.24329

Sa-Hong Kim¹, Franco José Signorini², Kyoyoung Park¹, Chungyoon Kim¹, Jeesun Kim¹, Yo-Seok Cho¹, Seong-Ho Kong^1,3,4, Do-Joong Park^1,3,4, Hyuk-Joon Lee^1,3,4, Han-Kwang Yang^1,3,4

¹Department of Surgery, Seoul National University Hospital, Seoul, Korea

²General Surgery Department, Private University Hospital of Córdoba, Córdoba, Argentina

³Department of Surgery, Seoul National University College of Medicine, Seoul, Korea

⁴Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea

Correspondence to: Han-Kwang Yang, Department of Surgery and Cancer Research Institute, Seoul National University Hospital, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 03080, Korea, Tel: +82-2-2072-2817, Fax: +82-2-766-3975, E-mail: hkyang@snu.ac.kr

Received 2024 December 27; Revised 2025 March 10; Accepted 2025 March 26.

Abstract

INTRODUCTION

Alterations in portal vein (PV) confluence are exceptionally rare, with limited reports in medical literature [1]. While most reports of PV anomalies emphasize intrahepatic structures and associated procedures [2], extrahepatic variations in PV confluence are of particular concern to gastric surgeons. Encountering these anomalies unexpectedly during suprapancreatic lymph node (LN) dissection, a critical step in gastric cancer surgery, can be highly challenging and potentially life-threatening.

Near-infrared (NIR) lymphangiography using indocyanine green (ICG) is emerging as a useful technique for visualizing the lymphatics during gastric cancer surgery [3]. The precision enabled by ICG-guided surgery is gaining popularity, facilitating meticulous LN dissection while minimizing the risk of injury to surrounding structures.

In this report, we present two cases of abnormal extrahepatic PV confluence, underscoring the importance of preoperative evaluation and identification of great vessel anomalies around the stomach to prevent complications. Furthermore, we highlight the promising role of the augmented imaging technology, such as NIR lymphangiography using ICG, in achieving oncological safety and precision through lymphatic navigation. This case report was conducted after approval from the Institutional Review Board of Seoul National University Hospital (IRB number: 2412-083-1596). Written informed consent for the publication was obtained in advance from the patients.

CASE REPORT

Case 1

A 57-year-old male patient, with no prior medical history or symptoms related to gastric cancer, was diagnosed with advanced gastric cancer (AGC) during a screening endoscopy. The endoscopy revealed an ulcerofungating AGC (Borrmann type II) located on the greater curvature side of gastric mid-antrum. A computed tomography (CT) scan showed wall thickening at the gastric antrum and small reactive perigastric LNs, with a preoperative clinical stage of T3N0M0. Additionally, the scan revealed a slight degree of gastrointestinal tract malrotation, characterized by a left-sided colon, right-sided small bowel, and polysplenia (Fig. 1). The patient was initially enrolled in a prospective clinical trial investigating the completeness of LN dissection during laparoscopic gastrectomy for gastric cancer. The trial utilized NIR lymphangiography with ICG, which was applied only after completing dissection of a certain topological LN station to detect any residual lymphatic tissue [4]. During surgery, an abnormally positioned main PV was observed anterior to the duodenum and pancreas (Fig. 2). Moreover, common hepatic artery (CHA) was entirely replaced by an aberrant CHA originating from the left gastric artery (LGA) (Fig. 3). Given these critical vascular anomalies, the patient was excluded from the clinical trial. Instead, NIR mode was continuously activated throughout the remaining surgery. Thereafter, we could safely complete LN dissection around the PV, as well as along the root of LGA and aberrant CHA (Supplementary Video 1).

Fig. 1

Gastrointestinal tract malrotation and polysplenia. (A, B) Left-sided colon and right-sided small bowel. (C, D) Polysplenia.

Fig. 2

Abnormal position of main portal vein (PV). Main PV was anteriorly positioned to the duodenum in laparoscopic view (A) and computed tomography (B).

Fig. 3

Replacing aberrant common hepatic artery. Replacing aberrant common hepatic artery originated from left gastric artery in laparoscopic view (A, B) and computed tomography (C–F). There was no typical common hepatic artery in its original location. The yellow arrow is the left gastric artery, and the red arrow is the replacing aberrant common hepatic artery.

Case 2

A 50-year-old male patient with a history of hypertension, heavy smoking, and giant bulla in both lungs was referred to our university hospital for AGC diagnosed by a screening endoscopy. The CT scan revealed a 6.8 cm ulceroinfiltrative (Borrmann type III) mass on the lesser curvature side of the gastric high body, involving the gastroesophageal junction, with several perigastric LNs suspicious of metastasis. Additionally, multiple prominent LNs were observed in the mediastinum (bilateral hilar area and bilateral interlobar area) and a few tiny nodules in the upper lobe of the lung, though their features were indeterminate for pulmonary metastases. The patient’s preoperative clinical stage was T4aN+. The patient consented to participate in clinical trial comparing neoadjuvant cisplatin and capecitabine (XP) versus neoadjuvant XP with pembrolizumab for three cycles. Following a staging laparotomy, open surgery was performed. The splenic vein (SV) lay anterior to the splenic artery (SA) near the pancreas tail, different from common anatomy (Fig. 4B). As the SV crossed posteriorly, overriding the SA near the pancreas body, it hindered the surgical approach to the celiac axis (CA) and the root of the LGA. The SV ultimately drained into the PV near the pancreas neck (Fig. 4).

Fig. 4

Abnormal position of SV. (A) SV was hindering the surgical approach to the CA and the root of the LGA in operative field. (B) SV lies anteriorly to SA near the splenic hilum. (C) SV crossed posteriorly, overriding the SA near the pancreas body, (D, E) then hindered the CA and LGA. SV, splenic vein; LGA, left gastric artery; SA, splenic artery; CA, celiac axis.

DISCUSSION

The anatomy of the PV confluence is typically stable and consistent. The main PV anatomy is formed by the confluence of the superior mesenteric vein, inferior mesenteric vein and SV posterior to the pancreas neck. However, this stability can be a double-edged sword, as rare and unexpected anomalies can be easily overlooked, increasing the risk of severe injury to these major draining veins during surgery.

The first case is related to the preduodenal-PV (PD-PV), where the PV runs ventrally to the duodenum and pancreatic head. This condition is often associated with intestinal malrotation and anomalies in the pancreas, spleen, or heart [5]. The embryological development of the PV system is complex, occurring between the 4th and 12th gestational weeks from the vitelline venous system in close relation with the umbilical venous system. The right and left vitelline veins communicate through three intervitelline anastomoses around the developing duodenum (cranial-ventral, dorsal, and caudal-ventral). Typically, the PV develops from the dorsal anastomosis, which is located posterior to the first portion of the duodenum. In cases of PD-PV, improper obliteration of the intervitelline anastomoses allows the caudal-ventral anastomosis, situated anterior to the duodenum, to persist and carry blood flow [6]. Other PV anomalies include congenital agenesis, duplication, aneurysm, thrombosis, cavernous transformation, and arterioportal shunt [2].

The anatomical variations of SV have been described in several studies. One cadaveric study described the SV running along the superior edge of the pancreatic tail for a 5-cm course before abruptly angling downward to enter the pancreatic body and joining the superior mesenteric vein to form the PV. In this arrangement, the SV did not obstruct access to the CA [7]. Another study reported an anteriorly placed SV relative to the pancreas without compromising the approach to the CA [8]. Zhu et al. [9] classified the SA into superficial, middle, and concealed type, and SV into superior, middle, and inferior type based on their position relative to the pancreas, without specific descriptions of unusual variations in SV. In a detailed report of spleen anatomy by Skandalakis et al. [10], it was noted that the SV could run anteriorly, both anteriorly and posteriorly, or posteriorly to the SA, with frequencies of 2%, 44%, and 54%. Additionally, Natsume identified a cranially positioned SV relative to SA in four out of 175 patients, though no specific topological relationship between the SV and the CA was described [11].

We successfully reconstructed the configuration of PV confluence of these two cases with three-dimensional volume rendering software (Fig. 5). The anomaly of PV confluence was challenging for suprapancreatic LN dissection during the gastric cancer surgery. Nevertheless, LN dissection was performed without any adverse event.

Fig. 5

Three-dimensional reconstruction of vascular anomalies. Abnormal arrangement of main portal vein and surrounding structures in first case (A), and abnormal arrangement of splenic vein and surrounding structures in second case (B, C) were three-dimensionally reconstructed. The blue arrow is anteriorly positioned main portal vein, and the brown arrow is duodenal 1st portion. LGA, left gastric artery; CA, celiac axis.

Image-guided surgery is increasingly utilized with the advancement in precision surgery [12]. ICG, first approved for diagnostic use in 1956, is a non-radioactive dye that emits NIR light, capable of penetrating tissue to depths from several millimeters to a few centimeters. ICG is not metabolized in the body and is excreted exclusively by the liver, with a plasma half-life of 3 to 4 minutes. It is neither reabsorbed in the intestine nor undergoes enterohepatic recirculation [13]. NIR imaging with ICG, an augmented imaging technology, has been applied to various medical fields, such as measuring hepatic function, assessing hepatic blood flow and cardiac output, localizing anatomical structures in specialized vascular surgeries [13], and LN mapping during cancer surgeries [14]. In laparoscopic and robotic surgery, ICG can be administered intravenously to assessment of organ perfusion or through endoscopic submucosal injection for LN mapping [15]. While the potential of this technology should be further investigated in future studies, it is evident that ICG-enhanced imaging provides significantly improved lymphatic navigation. Supplementary Video 1 demonstrates the application of ICG-enhanced lymphatic navigation in avoiding vascular injury when encountering unexpected anatomical anomalies, resulting in safe and precise surgery without any complications.

In conclusion, unexpected extrahepatic alterations in PV confluence, which is exceedingly infrequent, can lead to significant surgical risks during suprapancreatic LN dissection in gastric cancer surgery. This report presents two cases, emphasizing the critical importance of comprehensive preoperative evaluation for great vessel anomalies around the stomach. NIR lymphangiography with ICG, a promising method of augmented imaging technology, can enhance oncological safety and precision while minimizing intraoperative complications.

SUPPLEMENTARY MATERIALS

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