Pitfalls in the surgical treatment of insulinoma

doi:10.1067/msy.2002.128610

Surgery

Volume 132, Issue 6, December 2002, Pages 1040-1049

Presented at the 23rd Annual Meeting of the American Association of Endocrine Surgeons, Banff, Alberta, Canada, April 7-9, 2002.

https://doi.org/10.1067/msy.2002.128610 Get rights and content

Abstract

Background. In the 75 years since an insulinoma was first described, the challenge for the surgeon has been one of localization. The combination of endoscopic ultrasound (EUS) or intraoperative ultrasound and operative palpation has led to nearly 100% success rate at primary operation in experienced institutions. However, 13% of patients at referral centers undergo reexploration, which has an increased morbidity. With more successful localization modalities, the operative failures have become more challenging than ever. Methods. During the past 35 years, we have treated 118 cases of sporadic insulinoma. Technical advances in EUS have led to preoperative identification of more than 90% of insulinomas. Despite this success we have become increasingly aware of the limitations of EUS in the surgical treatment of insulinoma. We present the pitfalls of 6 recent cases. Results. The limitations of EUS include the assessment of malignancy, the identification of pedunculated or adjacent lesions, the evaluation of distal pancreatic lesions, and the differentiation of larger homogeneous tumors from surrounding parenchyma. Conclusions. The surgical challenge in the treatment of insulinomas has transformed from one of localization to one of recognizing the limitations of our current localization modalities. By sharing our experience with recent difficult cases, we guide the surgeon to greater success and the patient to decreased morbidity. (Surgery 2002;132:1040-9.)

Section snippets

Methods

There have been 118 cases of sporadic insulinoma during the past 35 years at the University of Michigan Medical Center. We present the pitfalls of 6 recent cases in which we followed our current algorithm (Fig 1).

. Algorithm of management plan for localization and treatment of sporadic insulinoma.

Their relevance in view of our current knowledge of the disease, management strategies, and localization modalities is discussed.

Case 1

A 50-year-old man presented with symptomatic hypoglycemia for several years. After 70 hours of fasting he became symptomatic with a serum glucose level of 31 mg/dL and an insulin/glucose ratio greater than 0.5. A presumptive diagnosis of sporadic insulinoma was made on the basis of a negative family history for MEN I.

A computed tomography (CT) scan of the liver and pancreas was negative for a mass or metastatic disease. EUS localized a 1.7 × 1.2 cm hypoechoic homogeneous mass in the pancreatic

Discussion

In 1929 the first successful surgical removal of an insulinoma was performed by Roscoe Graham in Toronto.⁶ It was not until 15 years later that the clinical diagnosis based on Whipple's triad was first described.⁷ However, the primary challenge has been localization rather than diagnosis or surgical technique. Conventional imaging has a wide range of accuracy (Table I).8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19

. Accuracy comparison of localization modalities

Author	Angiography	CT	EUS	IOUS	Abdominal US

Conclusion

The surgical challenges that we have presented revolve around the limitations of EUS. The SAS test for regionalization of the tumor is complementary to the EUS in cases in which localization is questionable. Surgical failures result from the inability to discern malignancy intraoperatively, multiple foci of disease, islet cell hyperplasia or nesidioblastosis, and inexperience. Intraoperative insulin assays may lead to a reduction in operative failures by identifying persistent disease.

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Increasing evidence suggests that migraine may be the result of an impaired brain glucose metabolism. Several studies have reported brain mitochondrial dysfunction, impaired brain glucose metabolism and gray matter volume reduction in specific brain areas of migraineurs. Furthermore, peripheral insulin resistance, a condition demonstrated in several studies, may extend to the brain, leading to brain insulin resistance. This condition has been proven to downregulate insulin receptors, both in astrocytes and neurons, triggering a reduction in glucose uptake and glycogen synthesis, mainly during high metabolic demand. This scoping review examines the clinical, epidemiologic and pathophysiologic data supporting the hypothesis that abnormalities in brain glucose metabolism may generate a mismatch between the brain's energy reserve and metabolic expenditure, triggering migraine attacks. Moreover, alteration in glucose homeostasis could generate a chronic brain energy deficit promoting migraine chronification. Lastly, insulin resistance may link migraine with its comorbidities, like obesity, depression, cognitive impairment and cerebrovascular diseases.
Although additional experimental studies are needed to support this novel “neuroenergetic” hypothesis, brain insulin resistance in migraineurs may unravel the pathophysiological mechanisms of the disease, explaining the migraine chronification and connecting migraine with comorbidities. Therefore, this hypothesis could elucidate novel potential approaches for migraine treatment.
Intrapancreatic accessory spleen: Findings on MR imaging and CT
2022, Surgery Open Digestive Advance
Although intrapancreatic accessory spleen (IPAS) are infrequently noticed radiologically, they have been reported up to 2, 8% in Autopsies. The aims of this study were to describe the imaging characteristics of IPAS using computed tomography (CT) and/or magnetic resonance imaging (MRI) to prevent an unnecessary surgery.
During last 7 years, 5 consecutive patients with incidental intrapancreatic accessory spleen (IPAS) on the tail of pancreas which radiologically mimicked a neuroendocrine pancreatic tumor, surgically treated in our university hospital. Preoperative CT studies (4 of 5 patients) and MRI (2 of 5 patients, one patient had both CT and MR images), operation reports and pathological diagnoses were analyzed retrospectively. For each lesion, images were analyzed based on the characteristic signal intensities on MRI or density of the lesion on CT images and presence of contrast enhancement. Pathologic correlation was available for the lesions.
The female-to-male ratio was 2:3, with a mean age of 56 years (age range, 42–72 years). Incidental lesion findings were due to imaging studies using magnetic resonance imaging and/or computed tomography. In all the patients there was just one lesion on the tail of pancreas. On all the MR images (2 of 5 patients), a focal pancreatic lesion that was in compared to the rest of pancreas hypointense on T1-weighted sequences were detected, these lesions were hyperintesne on T2-weighted sequences; and enhanced more than the pancreas tissue in contrast enhanced series; however, the lesions were with the same intensity in compared to spleen in all the sequences. The enhancement pattern of the lesion was evaluated as serpiginous on early postgadolinium sequences. On all CT studies (4 of all 5 patients), there were no detectable lesions on pre-contrast series; however, on all arterial and venous series lesions were hyperdens in contrast to the rest of pancreas. The lesions had the same density of spleen in all series. In both MRI and CT images there were No adenopathy in the abdomen. Tumor size was among min. 9 × 12 mm to max. 16 × 18 mm. Pathological findings were intrapancreatic accessory spleen (IPAS) in all the cases. One patient had a pathological finding of Leiomyoma of the stomach too.
Radiologists and Surgeons should be aware that an incidental finding of a subtle well-marginated, rounded solitary lesion on the tail of pancreas on the CT or MR images which matches the density/or intensity of the spleen on all phases/ or sequences could be an intrapancreatic accessory spleen (IPAS); Therefore, an IPAS has to be excluded in asymptomatic patients with a lesions in the pancreatic tail before unnecessary surgery.
Pancreatic neuroendocrine tumors
2013, Current Problems in Surgery
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Tumors are imaged less (37%-60%) in the body and tail, which can only be viewed through the stomach.87 Finally, EUS is limited in assessment of malignancy, identification of pedunculated tumors, and differentiation of some large tumors from the pancreatic parenchyma.88 In patients with negative results after noninvasive imaging studies and EUS, calcium arteriography may be obtained.
Pedunculated insulinoma on the anterior border of the head of the pancreas: An unusual location to be aware of
2013, Diagnostic and Interventional Imaging
Citation Excerpt :
CT and MRI contrast resolution is not good enough for left pancreatic locations where small insulinomas may develop close to and be confused with splenic vessels [5]. Pedunculated forms are not common and amount to less than 10% of cases of sporadic pancreatic insulinomas [5,9,10]. They are also a classic and significant source of failure of preoperative imaging evaluation [5,9].
Neuroendocrine Tumors of the Pancreas
2012, Shackelford's Surgery of the Alimentary Tract: Volume 1-2, Seventh Edition
Preoperative tumor studies using MRI or CT in patients with clinically suspected insulinoma
2011, Pancreatology
Purpose: Insulinomas are rare tumors that originate from the islet cells of the pancreas. The aims of this study were to localize insulinomas preoperatively using CTand/or MRI in correlation with postoperative pathological results. Patients and Methods: Between December 2001 and June 2010, 27 consecutive patients with clinically suspected insulinoma were surgically treated in our university hospital. Preoperative CT (14 of 27 patients) and MRI studies (14 of 27 patients, one patient had both MRI and CT), operation reports, intraoperative ultrasonography reports, and pathological diagnoses were analyzed retrospectively. For each lesion, images were analyzed based on the presence of enhancement or the characteristics of signal intensities. Pathologic correlation was available for all the lesions. Results: The female: male ratio was 2.9, with a mean age of 47.5 years (range 12–82). Preoperative tumor localization was achieved by means of MRI and CT. A focal pancreatic lesion, which was hypointense on T1-weighted sequences, was detected on all the MR images (14 of 27 patients; 100%). These lesions were isointense (4 cases) to slightly hyperintense (10 of 14 cases) on T₂-weighted sequences. In T₁-weighted fat-suppressed contrast-enhanced sequences, there were two types of enhancement: homogeneously hyperintense lesions (in 10 of 14 cases) or peripherally hyper-, centrally isointense (in 4 of 14 cases). On all the CT images (14 of 27 patients), there was no detectable lesion on precontrast series; on arterial series in 13 of 14 patients (arterial series has not been done in one patient), lesions enhanced hypervascular in contrast to the rest of the pancreas with a mean enhancement of 147 HU (range 113–248) and 95 HU (range 65–141), respectively. On venous series in 13 of 14 patients (venous series has not been done in one patient), there was an enhanced lesion in contrast to the rest of the pancreas with a mean enhancement of 110 HU (range 91–151) and 86 HU (range 65–137), respectively. Intraoperative ultrasonography was performed in 11 of 27 patients to localize the tumor, which correlated with the results of the mentioned preoperative studies. Tumor size ranged from 9 × 11 to 31 × 37 mm. Enucleation was carried out in 14 patients, Whipple in 5, segmental resection in 3 and left distal pancreatectomy in 5 patients. The mortality rate was 0. Pathological findings were insulinoma or neuroendocrine tumors in 26 of 27 cases. One patient had a pathological finding of chronic pancreatic disease with intraepithelial neoplasia (grade 1A). Conclusion: We conclude that the preoperative localization of insulinoma in clinically suspected patients can be made on the basis of MRI and/or CT studies. A hallmark lesion is hypointense in T₁-weighted sequences, homogeneously or peripherally hyperintense in T₁-weighted fat-suppressed contrast-enhanced sequence using MRI (100% of cases) or/and a hypervascular enhanced lesion on arterial (100% of CT studies) and on venous series using CT (66.7% of CT studies).

View all citing articles on Scopus

^*: Reprint requests: Melanie L. Richards, MD, University of Texas Health Science Center at San Antonio, Department of Surgery, 7703 Floyd Curl Dr, San Antonio, TX 78229-3900.

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American Association of Endocrine SurgeonsPitfalls in the surgical treatment of insulinoma*

Abstract

Section snippets

Methods

Case 1

Discussion

Conclusion

Am J Surg

Curr Probl Surg

Am J Surg

Am J Gastroenterol

Surgery

Carcinoma of the islets of the pancreas: hyperinsulinism and hypoglycemia

JAMA

Results of a prospective strategy to diagnose, localize and resect insulinomas

Surgery

Reoperative insulinomas, 1927 to 1992: an institutional experience

Surgery

Reoperative surgery for organic hyperinsulinism: indications and operative strategy

World J Surg

Dysinsulinism: convulsions and coma due to islet cell tumor of the pancreas with operation and cure

JAMA

Hyperinsulinism in relation to pancreatic tumors

Surgery

American Association of Endocrine Surgeons
Pitfalls in the surgical treatment of insulinoma*