Case Report
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Sep 26, 2020; 8(18): 4169-4176
Published online Sep 26, 2020. doi: 10.12998/wjcc.v8.i18.4169
Insulinoma presenting with postprandial hypoglycemia and a low body mass index: A case report
Dana Prídavková, Matej Samoš, Roman Kyčina, Katarína Adamicová, Michal Kalman, Margita Belicová, Marián Mokáň
Dana Prídavková, Matej Samoš, Margita Belicová, Marián Mokáň, Clinic of Internal Medicine I, Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Martin 03601, Slovakia
Roman Kyčina, Clinic of Surgery and Transplant Center, Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Martin 03601, Slovakia
Katarína Adamicová, Michal Kalman, Department of Pathological Anatomy, Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Martin 03601, Slovakia
Author contributions: Prídavková D participated in the conception and design of the report and wrote the paper; Kyčina R, Adamicová K, Kalman M, Belicová M and Mokáň M made substantial contributions to the acquisition, analysis and interpretation of the patient data; Samoš M and Belicová M were involved in the coordination and design of the report and revision of the manuscript; all authors read and approved the final manuscript.
Informed consent statement: Informed written consent was obtained from the patient for publication of this report and any accompanying images.
Conflict-of-interest statement: The authors declare that they have no conflict of interest.
CARE Checklist (2016) statement: The authors have read the CARE Checklist (2016), and the manuscript was prepared and revised according to the CARE Checklist (2016).
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Dana Prídavková, MD, PhD, Doctor, Medical Assistant, Clinic of Internal Medicine I, Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Kollárova 2, Martin 03601, Slovakia. danapridavkova@gmail.com
Received: May 29, 2020
Peer-review started: May 29, 2020
First decision: June 13, 2020
Revised: June 23, 2020
Accepted: August 22, 2020
Article in press: August 22, 2020
Published online: September 26, 2020
Abstract
BACKGROUND

Insulinomas are the most common type of functioning endocrine neoplasms of the pancreas presenting hypoglycemic symptoms. Patients characteristically develop symptoms while fasting, but some patients have reported symptoms only in the postprandial state. Repeated and prolonged hypoglycemic episodes can reduce the awareness of adrenergic symptoms, and patients may have amnesia, which delays diagnosis.

CASE SUMMARY

We describe a case of a 24-year-old underweight patient who showed hypoglycemic symptoms for almost 6 years. Although patients with insulinoma characteristically develop symptoms while fasting, this young man had hypoglycemic symptoms up to one hour postprandially, especially after high-sugar meals and after physical activity. The fasting tests and imaging methods performed at local hospitals were evaluated as negative for abnormal results. However, brown adipose tissue exhibited increased metabolic activity, and some muscle groups had histological changes as indicated by positron emission tomography with 2-deoxy-2-[fluorine-18]fluoro-D-glucose integrated with computed tomography. Glycogen deficiency was also histologically confirmed. The patient’s symptoms progressed over the years and occurred more frequently, i.e., several times a month, and the patient had reduced awareness of adrenergic symptoms. The follow-up fasting test was positive, and the imaging results showed a tumor in the head of the pancreas. The patient underwent laparotomy with enucleation of the insulinoma.

CONCLUSION

Weight gain and fasting hypoglycemia are not necessarily characteristics of insulinoma. In prolonged cases, adrenergic symptoms can be suppressed.

Keywords: Brown adipose tissue, Glycogen deficit, Hypoglycemia, Insulinoma, Underweight, Case report

Core Tip: Postprandial hypoglycemia and hypoglycemia following physical exercise associated with unconsciousness/amnesia and a low body weight were the clinical features of insulinoma in a 24-year-old man for over 6 years. The consequences of the chronic counterregulatory adrenergic response were also indirectly indicated by the increased metabolic activity of brown adipose tissue and decrease in muscle glycogen content, although the fasting test and other imaging results were initially evaluated as normal. Therefore, if insulinoma is clinically suspected, the fasting test should be repeated. The patient was underweight with a very small amount of visceral fat, which increases the risk of perioperative complications.