Selective intra‐arterial calcium stimulation test for the localization of insulinomas: an Australian hospital experience

Abstract

Background: Insulinomas are rare tumours of the pancreas and the most common cause of hypoglycaemia in non-diabetic adults. They can be cured by surgery but require precise localization. The aim of this study was to assess the utility of the selective intra-arterial calcium stimulation test (SIACST) in patients with an insulinoma to correctly localize the tumour. Methods: Medical records of patients with a diagnosis of insulinoma or who underwent an SIACST were retrospectively reviewed. Localization of lesions by SIACST was compared to endoscopic ultrasound and radionuclide imaging studies and verified against findings at surgery. Results: A total of 24 patients (mean age 58 years, 16 females, 20 with insulinoma) underwent SIACST. The SIACST correctly localized the insulinoma in 17 of 20 patients (85%). Localization rate for computed tomography was 55% and 75% for endoscopic ultrasound and glucagon-like peptide-1 receptor scan. Conclusion: SIACST provided incremental diagnostic information in patients with insulinoma who had equivocal non-invasive imaging preoperatively. This technique remains an essential diagnostic tool when a lesion is not localized by other methods.

Insulinoma: Metastatic Recurrence 38 Years Following Initial Diagnosis in Pregnancy

“…In the recent episode, it is worth noting the usefulness of Ga-68 GLP-1 PET, as the only imaging study which was positive in this tiny tumor. Calcium stimulation testing, which has superseded portal venous sampling, also helped by confirming that the hypersecretion of insulin and proinsulin was originating in or near the pancreatic head [ 10 ].…”

Non-insulinoma pancreatogenous hypoglycemia syndrome due to nesidioblastosis following bariatric Roux-en-Y gastric bypass

“…This test works by injection of calcium gluconate followed by measurement of insulin secretion in several arteries surrounding the pancreas; a marked increase from baseline in these arteries identifies an area with increased β-islet cell activity [ 3 ]. Positive results in multiple locations both confirm pancreatic pathology as the origin of hypoglycemia while also leading away from the differential of insulinoma due to the lack of a single area of localization [ 4 , 5 ]. Interestingly, in this patient, SACST was positive in only the head of the pancreas, represented as increased insulin levels in the gastroduodenal artery.…”

Utility of 68Ga‐DOTA‐Exendin‐4 positron emission tomography–computed tomography imaging in distinguishing between insulinoma and nesidioblastosis in patients with confirmed endogenous hyperinsulinaemic hypoglycaemia

“…If Exendin imaging suggests the presence of an insulinoma, endoscopic ultrasound may be used to confirm the location. CaS is an important alternative to confirm the presence of an insulinoma or, if uniform pancreatic Exendin uptake is seen, suggesting the presence of nesidioblastosis 5,6 . If Exendin scan does not demonstrate an insulinoma, additional SSR‐2 and/or 17 FDG imaging should also be considered.…”

“…The current gold standard, selective arterial calcium stimulation and venous sampling studies (CaS), had higher sensitivity (85%) but limited localisation 4–6 . There is potential merit in non‐invasive approaches to diagnosis that would replace or complement the need for invasive CaS.…”