Preoperative vascular simulation for distal bile duct cancer with a preduodenal portal vein: A case report

Abstract

BACKGROUND

Preduodenal portal vein (PDPV) is a rare congenital vascular anomaly in which the portal vein courses anterior to the duodenum. This anomaly may increase the risk of catastrophic vascular injury during pancreaticobiliary surgery, particularly when accompanied by additional anatomical abnormalities.

CASE SUMMARY

A 67-year-old man presented with progressive jaundice and was diagnosed with distal bile duct cancer. Contrast-enhanced computed tomography revealed a PDPV, celiac axis stenosis due to median arcuate ligament syndrome, intestinal malrotation, polysplenia, and severe hypoplasia of the pancreatic body and tail. Based on careful review of the original computed tomography dataset and three-dimensional imaging, a preoperative schematic illustration-based vascular simulation was created to integrate complex anatomical and hemodynamic findings and assess the extent of preservable pancreatic parenchyma. Because the pancreatic body and tail were markedly hypoplastic, and preservation of a functionally adequate pancreatic remnant was considered unfeasible, total pancreatectomy was selected. Intraoperatively, the anomalous portal vein and prominent pancreaticoduodenal collaterals were confirmed, and total pancreatectomy was completed safely after verification of adequate hepatic arterial inflow. Histopathology revealed distal bile duct cancer (pT3N0M0) with negative margins, consistent with R0 resection.

CONCLUSION

Preoperative illustration-based vascular simulation can facilitate safe and individualized surgical planning in pancreaticobiliary malignancies associated with PDPV.

Key Words: Preduodenal portal vein; Distal bile duct cancer; Total pancreatectomy; Median arcuate ligament syndrome; Vascular anomaly; Preoperative simulation; Case report

Core Tip: Preduodenal portal vein is an extremely rare congenital vascular anomaly that can complicate pancreaticobiliary surgery. We report a case of distal bile duct cancer with preduodenal portal vein and multiple congenital anomalies, including median arcuate ligament syndrome, intestinal malrotation, polysplenia, and pancreatic hypoplasia. Preoperative illustration-based vascular simulation, generated through careful review of the original computed tomography dataset, enabled precise understanding of the anomalous anatomy and clinically relevant collateral flow patterns. This directly influenced the surgical strategy, allowing safe completion of total pancreatectomy. This case highlights the practical value of careful preoperative vascular assessment and surgeon-directed schematic integration in complex pancreaticobiliary surgery.

INTRODUCTION

Preduodenal portal vein (PDPV) is a rare congenital vascular anomaly in which the portal vein courses anterior to the duodenum[1,2]. PDPV demonstrates a wide spectrum of clinical presentations, ranging from asymptomatic cases to gastrointestinal obstruction. Most reported cases occur in pediatric patients or are discovered incidentally during surgery, whereas reports of pancreaticobiliary surgery in adult patients with PDPV remain limited[1,2]. Adult cases of PDPV described in the literature are scarce and largely confined to sporadic case reports.

PDPV is frequently associated with other congenital anomalies, including pancreatic developmental abnormalities, intestinal malrotation, and visceral heterotaxy, such as polysplenia or left isomerism, suggesting a common embryological background[3,4]. These associated abnormalities may further complicate surgical anatomy and make operative planning more challenging. In particular, when vascular anomalies coexist with abnormalities of pancreatic development or intestinal rotation, safe pancreaticobiliary surgery requires precise preoperative anatomical assessment and careful strategic planning.

Reports describing pancreaticobiliary malignancies requiring major pancreatic resection in patients with PDPV are particularly rare[5,6]. Consequently, the optimal surgical strategy in such complex anatomical settings has not been established. Here, we report a case of distal bile duct cancer with PDPV and multiple congenital anomalies, including hypoplasia of the pancreatic body and tail, intestinal malrotation, polysplenia, and median arcuate ligament syndrome (MALS), in which preoperative vascular simulation directly influenced surgical decision-making and enabled safe completion of total pancreatectomy. To our knowledge, reports describing pancreaticobiliary malignancy associated with a PDPV in which preoperative vascular simulation directly influenced the surgical strategy remain extremely limited.

CASE PRESENTATION

Chief complaints

A 67-year-old man presented with progressive jaundice.

History of present illness

The patient developed progressive jaundice and was referred to our hospital for further evaluation.

History of past illness

The patient had a history of diabetes mellitus treated with insulin therapy. No other significant past medical history was noted.

Personal and family history

The patient had a personal history of diabetes mellitus treated with insulin therapy. No remarkable family history was noted.

Physical examination

Physical examination revealed scleral icterus.

Laboratory examinations

Laboratory testing revealed elevated total bilirubin [165.9 μmol/L (9.7 mg/dL)], alkaline phosphatase (300 U/L), and γ-glutamyl transpeptidase (403 U/L), consistent with obstructive liver dysfunction. Serum carbohydrate antigen 19-9 was elevated to 497.6 U/mL, and carcinoembryonic antigen was 8.0 μg/L (8.0 ng/mL).

Imaging examinations

Contrast-enhanced computed tomography (CT) demonstrated a tumor in the distal bile duct causing biliary obstruction. Careful review of the axial, coronal, and sagittal images revealed that the portal vein coursed anterior to the duodenum, consistent with a PDPV (Figure 1A). Focal stenosis at the origin of the celiac artery suggested MALS (Figure 1B). Intestinal malrotation and polysplenia were also identified (Figure 1C). Careful review of the original CT dataset, together with three-dimensional reconstruction using SYNAPSE VINCENT (FUJIFILM, Tokyo, Japan), confirmed the anomalous course of the portal vein and enabled preoperative schematic illustration-based vascular simulation (Figures 2 and 3). This process also highlighted prominent pancreatic collateral circulation associated with MALS and marked hypoplasia of the pancreatic body and tail (Figure 2B).

Figure 1 Contrast-enhanced computed tomography findings. A: Multiplanar computed tomography (CT) images (axial, coronal, and sagittal views) showing the portal vein coursing anterior to the duodenum (orange arrows), consistent with a preduodenal portal vein. The yellow dotted lines indicate the duodenal wall; B: Sagittal CT image demonstrating focal stenosis at the origin of the celiac artery (orange arrowhead), suggesting median arcuate ligament syndrome; C: Axial CT image showing multiple spleens (black arrow), consistent with polysplenia.

Figure 2 Three-dimensional reconstruction of vascular anatomy. A: Three-dimensional computed tomography reconstruction demonstrating the portal vein running anterior to the duodenum (green star) and the duodenum (orange diamond); B: Prominent dilatation of pancreaticoduodenal arcade collaterals associated with median arcuate ligament syndrome, and marked hypoplasia of the pancreatic body and tail, indicated up to the level of the yellow arrowhead line.

Figure 3 Schematic illustration of preoperative surgical planning. A schematic drawing generated from a careful review of the original computed tomography dataset, illustrating the anomalous portal vein, hypoplastic pancreas, surgically relevant collateral vessels, and the planned extent of resection. Orange lines indicate the planned transection lines, and orange arrows indicate the planned division of the median arcuate ligament. CA: Celiac artery; LGA: Left gastric artery; MAL: Median arcuate ligament; RGEA: Right gastroepiploic artery; SA: Splenic artery; SV: Splenic vein; RGEV: Right gastroepiploic vein; SMA: Superior mesenteric artery; CBD: Common bile duct; ASPDA: Anterior superior pancreaticoduodenal artery.

FINAL DIAGNOSIS

Distal bile duct cancer with PDPV and multiple congenital anomalies.

TREATMENT

Because the pancreatic body and tail were markedly hypoplastic, resection of the pancreatic head would not have left a functionally adequate pancreatic remnant; therefore, total pancreatectomy with bile duct resection and biliary reconstruction was planned. Laparotomy revealed severe intra-abdominal adhesions. Intestinal malrotation was confirmed, and Ladd’s band was divided (Figure 4A). The portal vein was exposed and confirmed to course anterior to the duodenum as predicted (Figure 4B). Markedly dilated pancreatic arcade vessels were also observed (Figure 4C). To assess hepatic arterial inflow, the first branch of the superior mesenteric artery (SMA) and the anterior superior pancreaticoduodenal artery were temporarily clamped to interrupt SMA-derived inflow and exclude supplementary collateral inflow through the pancreaticoduodenal arcade (Supplementary Figure 1). Hepatic inflow was judged to be acceptable based on Doppler examination, palpation of preserved pulsation in the proper hepatic artery, and maintained liver parenchymal color. The median arcuate ligament was also divided as an adjunctive maneuver, and total pancreatectomy was then safely completed (Figure 4D).

Figure 4 Intraoperative findings. A: Ladd’s band associated with intestinal malrotation is identified and divided; B: The portal vein is seen coursing anterior to the duodenum; C: Markedly dilated pancreatic arcade; D: The first branch of the superior mesenteric artery and anterior superior pancreaticoduodenal artery are temporarily clamped with vascular clips to confirm adequate arterial inflow from the proper hepatic artery. ASPDA: Anterior superior pancreaticoduodenal artery; SMA: Superior mesenteric artery.

OUTCOME AND FOLLOW-UP

The operation time was 603 minutes, and blood loss was 400 mL. The postoperative course was uneventful, and the patient was discharged on postoperative day 15. The patient had already been receiving insulin therapy before surgery, and glycemic control was continued after total pancreatectomy with adjusted basal-bolus insulin therapy. Pancreatic enzyme replacement therapy with pancrelipase (1800 mg/day) was also prescribed. At the 3-month follow-up visit, no clinical evidence suggestive of recurrence was observed, although postoperative CT had not yet been performed at that time. Histopathological examination revealed distal bile duct cancer (pT3N0M0) with negative resection margins, consistent with R0 resection.

DISCUSSION

Pancreaticobiliary surgery in the presence of complex congenital vascular anomalies poses a substantial risk of catastrophic vascular injury. Careful preoperative anatomical assessment is therefore essential for determining the optimal surgical strategy. When PDPV coexists with additional anomalies, such as MALS and intestinal malrotation, surgical anatomy may deviate markedly from conventional landmarks, further increasing procedural complexity.

PDPV is extremely rare, and is often discovered incidentally during surgery[1,2]. Previous studies have emphasized that unrecognized PDPV may lead to catastrophic vascular injury[2]. In the present case, PDPV was diagnosed preoperatively, and schematic vascular mapping enabled precise understanding of its relationship to surrounding structures, thereby reducing the risk of misidentification.

Rather than representing an isolated vascular anomaly, PDPV is considered part of a broader embryological spectrum, because it frequently coexists with pancreatic developmental abnormalities, intestinal malrotation, and heterotaxy syndromes[3,4]. In our patient, severe hypoplasia of the pancreatic body and tail and intestinal malrotation were recognized preoperatively, suggesting difficulty in identifying normal pancreatic parenchyma and necessitating meticulous surgical planning. In this case, pancreaticoduodenectomy was not considered a feasible parenchyma-preserving alternative, because the pancreatic body and tail were markedly hypoplastic, and resection of the pancreatic head would not have left a functionally meaningful pancreatic remnant. Although this anatomical assessment strongly supported total pancreatectomy, formal preoperative endocrine and exocrine functional assessment was not available and should be acknowledged as a limitation. Previous reports of adult malignant cases associated with PDPV remain very limited[5,6], underscoring the lack of established surgical strategies for such patients.

An additional important feature of this case was concomitant MALS, which further altered the peripancreatic vascular anatomy. MALS can cause celiac axis stenosis and promote collateral arterial flow through the pancreaticoduodenal arcade[7,8]. In the present case, preoperative imaging and vascular simulation suggested altered hepatic inflow secondary to MALS, with possible dependence on pancreaticoduodenal collateral pathways. This preoperative recognition was important, because it allowed strategic planning of intraoperative vascular assessment and safer operative decision-making. Thus, the value of preoperative simulation in this case was not merely descriptive, but functional, as it directly influenced both the extent of pancreatic resection and informed intraoperative vascular assessment.

Intraoperative vascular assessment in the setting of MALS should be interpreted cautiously. In the present case, temporary clamping of the first branch of the SMA and the anterior superior pancreaticoduodenal artery was used as a practical maneuver to assess whether hepatic arterial inflow remained acceptable after interruption of SMA-derived and pancreaticoduodenal arcade-derived collateral flow. Adequacy was judged qualitatively by Doppler examination, palpation of arterial pulsation, and preserved liver parenchymal color. Because quantitative recorded flow data were not available, this assessment should be regarded as a qualitative intraoperative judgment rather than a formal hemodynamic analysis. Similarly, “preoperative vascular simulation” in this case did not refer to quantitative computational modeling or virtual reality-based planning, but rather to a surgeon-directed process based on a detailed review of the original CT dataset, three-dimensional reconstruction using SYNAPSE VINCENT, and schematic integration of anatomically and hemodynamically relevant findings for operative planning. The value of this approach was not quantitative prediction, but the ability to translate complex anatomical and collateral flow information into a practical, decision-oriented operative roadmap. Division of the median arcuate ligament was performed as an adjunctive maneuver, and postoperative CT angiography was not performed, because there were no biochemical or clinical findings suggestive of impaired hepatic perfusion. Although workstation-based three-dimensional reconstruction is useful for anatomical visualization, direct schematic reconstruction from the original CT dataset may allow more explicit incorporation of surgically relevant details, including vessel caliber, fine collateral pathways, and their hemodynamic relevance. This was particularly important in the setting of MALS, in which small collateral vessels can be critical for interpretation of hepatic inflow. Three-dimensional surgical simulation has also been reported to be useful for preoperative assessment in pancreatoduodenectomy[9,10]. By manually integrating these findings, the schematic mapping translated complex anatomical and hemodynamic information into a decision-oriented operative roadmap. The preoperative schematic illustration showed good concordance with the intraoperative findings in terms of vessel course and the relative impression of vessel caliber, facilitating intraoperative identification of the aberrant vessels and clarification of the anticipated transection lines, the limited preservable pancreatic remnant, and vascular risk points. Because previously reported adult PDPV cases associated with pancreaticobiliary malignancy are extremely limited and heterogeneous in terms of associated anomalies and operative strategy, the present case does not establish superiority of any particular simulation method but rather illustrates the practical usefulness of careful CT-based vascular assessment and surgeon-directed schematic integration for operative planning in highly complex anatomy. Taken together, these findings support the concept that PDPV should be recognized as a strategy-changing vascular anomaly rather than a simple anatomical variant.

CONCLUSION

Preoperative vascular simulation may play an important role in surgical planning for pancreaticobiliary malignancies associated with complex congenital vascular anomalies such as PDPV. It may facilitate safe pancreaticobiliary surgery by enabling individualized operative planning and appropriate intraoperative decision-making.