
==== Front
Endosc Ultrasound
Endosc Ultrasound
EUSJ
Endoscopic Ultrasound
2303-9027
2226-7190
Lippincott Williams & Wilkins

EUSJ_240059
10.1097/eus.0000000000000058
00009
3
Images and Videos
Hormonal changes revealed by selective arterial calcium injection tests in patients with insulinoma treated with EUS–guided ethanol injection
Matsumoto Kazuyuki 1 ∗
Komatsubara Motoshi swe_etfish@yahoo.co.jp
2
Inagaki Kenichi kenina@md.okayama-u.ac.jp
3
Kato Hironari katou-h@cc.okayama-u.ac.jp
1
Otuka Motoyuki otsukamoto@gmail.com
1
1 Department of Gastroenterology and Hepatology, Okayama University Hospital, Okayama, Japan
2 Department of Endocrinology, Okayama City Hospital, Okayama, Japan
3 Department of Nephrology, Rheumatology, Endocrinology and Metabolism, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
∗ Address for correspondence: Department of Gastroenterology and Hepatology, Okayama University Hospital, 2-5-1 Shikata-cho, Okayama 700-8558, Japan. E-mail: matsumoto.k@okayama-u.ac.jp (K. Matsumoto).
May-Jun 2024
31 5 2024
13 3 193195
19 11 2023
14 3 2024
Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc on behalf of Scholar Media Publishing.
2024
Wolters Kluwer on behalf of Scholar Media Publishing.
https://creativecommons.org/licenses/by-nc-nd/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

OPEN-ACCESSTRUE
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pmcEUS–guided ethanol injection (EUS-EI) has recently been proposed as a therapeutic option for patients with functional pancreatic neuroendocrine neoplasms (PNENs), and some reports have described the improvement of patients’ hormone-related symptoms after treatment.[1–4] However, few studies have conducted a detailed hormonal evaluation after treatment.[1,2] The selective arterial calcium injection (SACI) test is a useful method for evaluating changes in hormonal dynamics in patients with functional PNENs.[5] We herein report the first case of insulinoma in which SACI tests could be performed before and after EUS-EI.

A 78-year-old man with hypoglycemia was referred to our hospital for a further examination and treatment. Nonsymptomatic hypoglycemia at night and early in the morning was repeatedly detected using flash glucose monitoring. A 72-hour fasting test revealed hypoglycemia (42 mg/dL) within 10.5 hours in the presence of inappropriate elevated serum insulin level of 9.7 μU/mL and C-peptide level of 2.54 ng/mL. Abdominal contrast-enhanced computed tomography (CE-CT) showed a 1-cm enhancing tumor in the pancreatic head [Figure 1]. In the SACI test, calcium infusion into the gastroduodenal artery (GDA) led to a remarkable increase in venous insulin levels, whereas stimulation of other arteries, including the hepatic artery, did not induce insulin overproduction, suggesting that the pancreatic head lesion was an insulin-producing tumor [Figure 2A]. An EUS-guided biopsy confirmed the tumor to be a PNEN with grade 1 histology. Considering the patient’s age and surgical invasion of the pancreaticoduodenectomy, we decided not to surgically remove the tumor, performing EUS-EI instead. A 25-gauge needle was advanced into the tumor, and 1.25 mL pure ethanol was injected until the hyperechoic blush extended to the tumor’s entire margin [Figure 3]. No procedure-related complications occurred. Three days after treatment, disappearance of tumor enhancement on CE-CT was confirmed [Figure 4]. In addition, a reevaluation of the SACI test showed markedly reduced insulin elevation induced by calcium infusion compared with the preoperative evaluation [Figure 2B]. No tumor recurrence on CE-CT and no hypoglycemic events were reported over 3 years of follow-up [Figure 5]. The SACI test after treatment is useful for evaluating efficacy against functional PNENs.

Figure 1 Contrast-enhanced computed tomography (CE-CT) images before treatment. (A) A 1.0-cm hypervascular tumor in the pancreas head (arrow). (B) Coronal image.

Figure 2 The selective arterial calcium injection (SACI) test. Calcium gluconate (0.025 mEq/kg) was injected into each artery (SMA, pSPA, dSPA, GDA, RHA, and LHA) for 30 seconds, and venous blood samples were collected from the right hepatic vein at specified intervals (pre, 30, 60, 90, and 120 seconds). Each calcium infusion was performed at least 5 minutes apart. (A) Venous insulin levels after calcium injection into the GDA significantly increased, suggesting that the lesion in the pancreatic head was an insulin-producing tumor. (B) After treatment, the pathological insulin elevation induced by calcium infusion into the GDA declined remarkably. SMA, superior mesenteric artery; pSPA, proximal splenic artery; dSPA, distal splenic artery; GDA, gastroduodenal artery; RHA, right hepatic artery; LHA, left hepatic artery.

Figure 3 EUS–guided ethanol injection images. (A) Before the treatment: a hypoechoic tumor in the head of the pancreas. (B) Immediately after the EUS-guided ethanol injection, 1.25 mL of pure ethanol was injected. (C) After the EUS-guided ethanol injection, the hyperechoic blush extended to the tumor’s entire margin. *Main pancreatic duct.

Figure 4 Contrast-enhanced computed tomography (CE-CT) images after the treatment. (A) Three days after the treatment: appearance of a low-density area without contrast enhancement (arrow). (B) Coronal image.

Figure 5 Follow-up images after the treatment. (A) Contrast-enhanced computed tomography (CE-CT) at 3 years after treatment: disappearance of contrast enhancement of the tumor in the pancreas head (circle). (B) EUS image at 1½ years after treatment: there was no low-echoic mass at the previous tumor site (circle). *Main pancreatic duct. SMV: superior mesenteric vein.

Conflicts of Interest

The authors declare that they have no financial conflict of interest with regard to the content of this report.

Declaration of Patient Consent

The authors certify that they obtained all appropriate patient consent forms. In this form, the patient gave his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published, and due efforts will be made to conceal his identity, but anonymity cannot be guaranteed.

Author Contributions

KM and KI drafted the manuscript. MK and HK contributed to the conception, design, and acquisition of the data. MO revised the manuscript for important content.

Source of Funding

This work was supported by Japan Agency for Medical Research and Development (AMED) (23ck0106900h0001).

Published online: 31 May 2024
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