Percutaneous radiofrequency ablation of pancreatic insulinoma: A case report and literature review

Abstract

Insulinomas are functional neuroendocrine neoplasms arising from the pancreatic islet cells resulting in excess insulin secretion and hypoglycemic episodes. Surgical resection is the standard treatment, but minimally invasive options such as radiofrequency ablation (RFA) have emerged as valuable alternatives, especially for nonsurgical candidates. We present the case of a 38-year-old male experiencing repeated episodes of critical hypoglycemia secondary to a pancreatic insulinoma, confirmed by elevated insulin and C-peptide levels and imaging findings. Initial surgical resection was unsuccessful due to intraoperative difficulty in localizing the lesion. The patient was subsequently treated with percutaneous RFA. Following the procedure, he developed mild pancreatitis, which was managed conservatively with complete resolution Follow-up at 12 months showed significant clinical improvement, normalization of insulin levels, and no evidence of tumor recurrence.

Introduction

Insulinomas develop from pancreatic beta cells to form rare neuroendocrine tumors which cause inappropriate insulin secretion that leads to repeated hypoglycemic episodes. The occurrence of insulinomas remains scarce with rates between 1 and 4 cases per million people per year yet these tumors create substantial patient health problems because of their clinical manifestations [1]. Surgical resection stands as the primary treatment approach which provides relief from symptoms to most patients [2]. However, surgery may not be feasible in certain patient populations due to factors such as advanced age, significant comorbidities, tumor location, or patient preference, necessitating alternative therapeutic approaches. Furthermore, surgical resection carries substantial risks, with both immediate and long-term complications. Approximately 35.4% of patients experience postoperative morbidity, pancreatic fistula develops in 14% to 58% of cases, and the mortality rate associated with this surgical approach is approximately 3.7% [3]. In recent years, there has been an increasing interest in minimally invasive therapeutic alternatives such as radiofrequency ablation (RFA), enables targeted tumor destruction through thermal energy delivery while minimizing damage to surrounding structures [4].

Although percutaneous RFA is widely used in the treatment of hepatic and renal cancers [5,6], its application in the treatment of pancreatic insulinoma remains limited to isolated case reports and small series and further evidence is needed to validate its clinical efficacy, safety, and long-term outcomes [7,8].

The purpose of this case report is to outline the successful use of percutaneous RFA in a patient who presented with a pancreatic insulinoma and subsequent intraprocedural hemorrhage. It also reviews the literature to provide an overview of the technical, safety, and efficacy aspects of this minimally invasive therapeutic approach.

Case presentation

A 38-year-old male presented with recurrent episodes of altered mental status secondary to severe hypoglycemia. These episodes frequently required emergent medical attention. Laboratory investigations revealed critical hypoglycemia with serum glucose levels persistently below 50 mg/dL. Concurrent biochemical evaluations demonstrated significantly elevated serum insulin levels (18.7 µIU/L; reference range: 1.0-9.0 µIU/L) and elevated C-peptide levels (4.3 ng/mL; reference range: 0.7–1.9 ng/mL). Given the clinical and biochemical findings, insulinoma was the primary diagnostic consideration. Subsequent contrast-enhanced computed tomography (CT) imaging demonstrated a solitary, well-defined hypervascular lesion measuring approximately 10 mm × 6 mm within the pancreatic parenchyma, localized in the body of pancreas (Fig. 1). Considering the severity of his symptomatic hypoglycemia, surgical resection was initially considered. However, during intraoperative exploration, the tumor could not be localized despite meticulous dissection, necessitating termination of the procedure without resection. The patient declined second surgical procedure and was subsequently referred for percutaneous ablation as an alternative minimally invasive approach. Coagulation studies were obtained prior to the procedure and found to be within normal limits (PT: 12.5 seconds; aPTT: 28 seconds; INR: 1.1). Under CT guidance with conscious sedation in supine position, percutaneous RFA was performed via an anterior transabdominal approach using a 17-gauge RFA probe (Valleylab, Tyco Health care, United States) powered by generator (COVIDIEN, RF ablation E series, Mansfield, United States). The RF electrode (15 cm length with 1 cm active tip) was positioned centrally within the lesion, and ablation was initiated (maximum output of 70 W- for 9 minute) (Fig. 2). During electrode retraction, real-time CT demonstrated a rapidly expanding hematoma measuring approximately 7.2 cm × 3.2 cm was identified at the ablation site (Fig. 3). Given the immediate visualization of bleeding, additional RFA was performed at multiple points at pancreatic surface and peripancreatic hematoma to achieve possible hemostasis (Fig. 4). Postprocedure CT imaging confirmed stabilization without further expansion of the hematoma. The patient was observed for 24 hours postprocedure and discharged home in stable condition. On postablation day 10, the patient returned complaining of generalized abdominal pain localized specifically to the epigastrium. Laboratory analysis showed significantly elevated serum amylase (350 U/L; reference range: 28–100 U/L) and lipase (210 U/L; reference range: 13–60 U/L), confirming the clinical suspicion of mild pancreatitis. He was managed conservatively with intravenous fluids, analgesics, and nil-per-os (NPO) protocol, resulting in resolution of symptoms within 48 hours. No further complications were noted. Follow-up evaluations demonstrated a sustained biochemical response, evidenced by a progressive decline in insulin levels from 18.7 µIU/L preablation to 3.76 µIU/L at 12 months postablation. Surveillance imaging at 1-year postablation demonstrated no evidence of recurrent or residual tumor, confirming the efficacy of the percutaneous RFA in achieving long-term control of the insulinoma (Fig. 5).

Fig. 1.

Pretreatment axial contrast-enhanced CT image demonstrating a well-defined, arterially enhancing mass (white arrow) located in the ventral aspect of the pancreatic body.

Fig. 2.

(A) Intra-procedural CT fluoroscopy image demonstrating placement of the RFA electrode centrally within the pancreatic lesion and (B) Schematic axial illustration demonstrating the percutaneous anterior transabdominal approach used for RFA of a pancreatic insulinoma ("Leiden - Drawing Cross-section upper abdomen with peritoneal lining - no labels" by Ron Slagter, license: CC BY-NC-SA).

Fig. 3.

Real-time CT image obtained immediately after electrode withdrawal reveals a newly formed, rapidly expanding hematoma (white arrows) adjacent to the ablation site.

Fig. 4.

Intra-procedural CT fluoroscopy image showing repeated RFA applications targeted within the peripancreatic hematoma. This was performed to achieve thermal hemostasis following procedure-related bleeding.

Fig. 5.

Axial contrast-enhanced CT image obtained at 12-month follow-up demonstrating complete resolution of the treated lesion with no evidence of tumor recurrence.

Discussion

Pancreatic insulinoma management has evolved with minimally invasive techniques, such as percutaneous and endoscopic ultrasound (EUS)-guided RFA, microwave ablation (MWA), and transarterial embolization.

Although percutaneous ablation of insulinoma began almost 6 years before EUS-guided ablation, the rapid growth of EUS-guided procedures has resulted in most treatments now being performed using the EUS approach [9]. Significant complications associated with EUS-guided methods include severe pancreatitis, pancreatic necrosis, bleeding, and perforation. Notably, one reported fatal case of fulminant necrotizing pancreatitis following EUS-guided RFA underscores the critical importance of careful patient selection and procedure execution [10].

Parallel to advances in endoscopy, interventional radiologists have taken a leading role in developing percutaneous ablation methods for pancreatic insulinomas. Additionally, percutaneous access offers greater anatomical reach; lesions in the pancreatic head, body, or tail can be targeted by selecting optimal percutaneous trajectories, unrestricted by endoscopic ultrasound windows or surgical exposure. Another benefit is that multiple treatment modalities can be combined or repeated by IR as needed – for example, an insulinoma can be initially treated via transarterial embolization to reduce vascular supply, followed by RFA to ablate the residual tumor tissue [11]. Table 1 summarizes a review of the literature and shows 5 successful cases of percutaneous ablation for insulinomas utilizing different IR techniques. Percutaneous RFA, MWA, and transarterial angioembolization were the ablation techniques used on the 1.2–3.7 cm treated lesions. Both RFA and MWA achieve tumor destruction through controlled thermal energy application. Compared to RFA, MWA generates higher instantaneous temperatures and operates over a broader energy field, which makes it especially effective for treating larger or highly vascular tumors, such as uterine fibroids [12]. All of the patients in these circumstances had clinical and biochemical recovery, with the symptomatic hypoglycemia resolved, and no serious side effects were noted. Throughout follow-up durations, which ranged from 2 months to thirty-six months, the positive results persisted without showing signs of recurrence. In our case, we did encounter a manageable complication (mild pancreatitis), whereas previous reports (Table 1) reported no major complications. This underscores that while percutaneous ablation is generally safe, pancreatitis remains a risk even outside of the EUS approach. Also, our case uniquely demonstrates that RFA itself can be employed to possibly achieve hemostasis in the event of a procedure-related hemorrhage – a technique that, to our knowledge, has not been reported in prior insulinoma ablation cases.

Table 1.

Summary of previously reported cases utilizing percutaneous ablative techniques for treatment of pancreatic insulinoma.

Author	Country	Gender	Age	Tumor size	Tumor location	Ablation technique	Complications	Recurrence	Follow-up
Limmer et al. [7]	Germany	Female	80	15 mm	Pancreatic tail	CT-guided percutaneous RFA	No pancreatitis; minimal peripancreatic inflammation on 35 d CT	None	7 months
Akhlaghpoor et al. [8]	Iran	Male	48	12 mm	Pancreatic head	CT-fluoroscopy–guided transcaval RFA	No pancreatitis, hemorrhage, or pseudocyst	None	3 years
Rossi et al. [13]	Italy	2 females	74 and 59	1.4 × 1.6 cm 1.3 × 1.6 cm	Pancreatic head-body Pancreatic head	Percutaneous RFA	None	None	1 months-
Chen et al. [14]	USA	Male	60	3.2 × 2.3 × 3.0 cm	Pancreatic neck	CT-fluoroscopy–guided microwave ablation	None	None	3 months
Ghorashi et al. [11]	USA	Male	62	16 mm	Pancreatic body	Embolization+ CT-guided percutaneous cryoablation	None	None	18 months

Current data can support the clinical efficacy and safety of percutaneous ablative procedures for treating insulinomas, despite the fact that they are primarily confined to case studies. This case contributes to the growing body of evidence by demonstrating a favorable 12-month outcome with no evidence of disease recurrence, along with an instance of intraprocedural complication management not previously described in the literature. considering the small number of reported cases and comparatively short follow-up sessions, larger-scale, prospective studies and multicenter registries are required. It is advised that interventional radiologist use these approaches cautiously until more solid data is available, carefully record clinical results, and continuously improve procedural protocols to improve patient safety and therapeutic effectiveness.

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Informed consent

Informed consent was obtained from the participant included in the study.

Consent for publication

Consent for publication was obtained for every individual person’s data included in the study.

Acknowledgments

None.

Data availability statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Patient consent

A written informed consent for publication of this case was obtained from the patient.