Elsevier

Endocrine Practice

Volume 19, Issue 4, July 2013, Pages 602-608
Endocrine Practice

Original Articles
Insulinoma
Endoscopic Ultrasonography - A Sensitive Tool in the Preoperative Localization of Insulinoma

https://doi.org/10.4158/EP12122.ORGet rights and content

ABSTRACT

Objective

A number of imaging modalities have been used in the preoperative localization of insulinomas. Computed tomography (CT) is the most commonly employed modality. Endoscopic ultrasound (EUS) allows the transducer to be placed in close proximity to the pancreas, thereby yielding higher quality images, which facilitates accurate localization, minimally invasive surgery, and a lower occurrence of residual tumors, all of which contribute to a better clinical outcome.

Methods

We analyzed the hospital records of all adult patients (age >18 years) diagnosed with insulinoma between October 2004 and September 2010. The diagnosis was based on the clinical practice guidelines of the American Endocrine Society. We compared the sensitivities of EUS and multidetector computed tomography (MDCT) in lesion.

Results

Eighteen patients were seen over a period of 6 years, and all underwent EUS. MDCT scans were carried out in 17 patients. EUS had greater sensitivity (89%) in localizing insulinomas compared to CT (69%). In this series, the lesions that were missed on CT but picked up on EUS were smaller (<12 mm, P<.001). Lesions that were near mesenteric vessels and those located in the head of the pancreas were more likely to be missed on CT.

Conclusions

EUS has a greater sensitivity in identifying and localizing insulinomas. As availability increases, EUS should be part of a preoperative insulinoma workup. (Endocr Pract. 2013;19:602-608)

Section snippets

INTRODUCTION

Most insulinomas are solitary, benign intrapancreatic tumors. As the current management strategy is to remove them with focused surgical dissection, preoperative localization is crucial(1). Currently, the most popular imaging modalities for anatomical localization are computerized tomography (CT) and magnetic resonance imaging (MRI). CT is usually the first choice as it is widely available. However, with the advent of more rapid contrast-enhanced multiphase image acquisition with breath-holding

METHODS

We analyzed the hospital records of all adult patients (age >18 years) diagnosed with an insulinoma between October 2004 and September 2010. Eighteen patients were diagnosed with insulinoma based on the clinical practice guidelines of the Endocrine Society (5). All patients underwent a supervised in-patient 72-hour fast that demonstrated low blood sugar and plasma glucose levels, corroborative symptoms, and concomitant elevations of insulin and C-peptide levels. C-peptide was measured in serum

RESULTS

Eighteen patients were diagnosed with an insulinoma between 2004 an 2010. The initial clinical features and laboratory parameters of all patients are shown in Table 1. The majority of patients were between 30 and 60 years old at presentation. The mean duration of symptoms prior to diagnosis was 30.2 months. The most common presenting symptom was hypoglycemia (66.9%), followed by loss of consciousness (61.1%), and seizures (44.4%). Weight gain occurred in 11 patients. The site of the pancreatic

DISCUSSION

Our results are comparable with one of the largest series published on insulinoma that described 10 years of data on 237 Mayo Clinic patients. Overall, 50% of our patients were females (57% in the Mayo Clinic series), and 70% had fasting hypoglycemia as the presenting symptom (73% in the Mayo Clinic series). We found that 67% of our patients had preoperative tumor localization (75% in the Mayo Clinic series) (7).

Hyperinsulinemic hypoglycemia was initially diagnosed by using the guidelines

REFERENCES (13)

There are more references available in the full text version of this article.

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