Combined use of calcium infusion localization and a minimally invasive surgical procedure in the management of insulinoma

Pancreatic insulinomas: Laparoscopic management

Insulinomas are rare pancreatic neuroendocrine tumors that are most commonly benign, solitary, and intrapancreatic. Uncontrolled insulin overproduction from the tumor produces neurological and adrenergic symptoms of hypoglycemia. Biochemical diagnosis is confirmed by the presence of Whipple’s triad, along with corroborating measurements of blood glucose, insulin, proinsulin, C-peptide, β-hydroxybutyrate, and negative tests for hypoglycemic agents during a supervised fasting period. This is accompanied by accurate preoperative localization using both invasive and non-invasive imaging modalities. Following this, careful preoperative planning is required, with the ensuing procedure being preferably carried out laparoscopically. An integral part of the laparoscopic approach is the application of laparoscopic intraoperative ultrasound, which is indispensable for accurate intraoperative localization of the lesion in the pancreatic region. The extent of laparoscopic resection is dependent on preoperative and intraoperative findings, but most commonly involves tumor enucleation or distal pancreatectomy. When performed in an experienced surgical unit, laparoscopic resection is associated with minimal mortality and excellent long-term cure rates. Furthermore, this approach confers equivalent safety and efficacy rates to open resection, while improving cosmesis and reducing hospital stay. As such, laparoscopic resection should be considered in all cases of benign insulinoma where adequate surgical expertise is available.

Setting the bar for laparoscopic resection of sporadic insulinoma

BACKGROUND

Laparoscopic insulinoma resection (LIR) for sporadic disease is increasingly supported as a feasible and safe operation in small series of patients. To determine whether LIR is an acceptable alternative to the open operation, it is necessary to compare LIR to historical controls. The purpose of this study was to identify the skills and technology needed for LIR and establish outcome standards.

METHODS

A database of patients with benign sporadic insulinoma who underwent an open procedure at the Mayo Clinic was reviewed for demographics, imaging, operative/pathology reports, and outcomes. Outcomes were compared to a world-wide meta-analysis of patients who had undergone LIR reported in the English literature between 1996 and 2009.

RESULTS

Two hundred fifteen patients underwent a primary open operation for benign sporadic insulinoma. Solitary tumors were found in 97%. Meta-analysis identified 232 patients who underwent LIR. The open and LIR groups underwent comparable operations that included enucleations (64 vs. 68%) and distal pancreatectomies (28 vs. 35%) (p = 0.06). The mean estimated blood loss, operating time, and length of stay were comparable between the open and LIR groups (p = NS). Pancreatic fistula occurred more often in the LIR group (24 vs. 11%, p < 0.05). A curative operation was performed in 98% of control patients and in 99% of the LIR group (p = NS).

CONCLUSIONS

Multiple insulinomas are rare and a focused resection guided by imaging may be performed. LIR is associated with an increased incidence of pancreatic fistula. Success of LIR will depend on accurate multimodality preoperative imaging, skilled use of lap-US to replace palpation for localization, and safe methods to dissect the tumor adjacent to the pancreatic duct.

[Giant insulinoma]

Islet-cell tumors are the most common neuroendocrine tumors that arise from the endocrine pancreas. They are typically benign and sporadic. Diagnosis is generally established late because clinical signs lack specificity. The insulinoma is difficult to localize since it is very small in size, often not exceeding 2cm. We report an exceptional case of giant insulinoma initially revealed by a pseudo-polycythemia in an 80-year-old man. He had been treated for hypertension for a few months. Routine biological investigations showed elevated hematocrit and haemoglobin, suggesting Vaquez disease. History taking revealed recent episodes of nocturnal agitation. On admission, he had reddish skin with a suspected enlarged spleen, but total blood volume was normal. Imaging studies showed a voluminous tumor located between the pancreas and the spleen. The presence of an insulinoma was confirmed on the basis of an elevated level of proinsulin at the time of an asymptomatic episode of hypoglycemia. Spleno-pancreatectomy was performed. Histopathological examination revealed a malignant, well-differentiated neuroendocrine malignant tumor.

Improved contemporary surgical management of insulinomas: a 25-year experience at the Massachusetts General Hospital

OBJECTIVE

To determine changes in the management strategy of patients with insulinomas and identify critical factors in patient outcome.

BACKGROUND

Pancreatic insulinomas are rare neoplasms that are present in various ways. The optimal approach to localization, operative management, and follow-up of insulinomas is undetermined.

METHODS

Sixty-one patients with a diagnosis of insulinoma requiring surgery at a tertiary care center between 1983 and 2007 were reviewed. Demographic details, mode of presentation, preoperative localization, operative procedures, and pathology data were assessed. The effect of different factors on survival was determined.

RESULTS

Seven of 61 (11%) patients had a diagnosis of multiple endocrine neoplasia-type 1 (MEN-1). Multiple insulinomas were noted in 8% of cases and were more common in MEN-1 patients. The overall rate of malignancy was 8%. Confusion (67%), visual disturbances (42%), and diaphoresis (30%) were the most common presenting symptoms. Weight gain was noted in 44% of patients. The median duration of symptoms before diagnosis was 18 (1-240) months. The sensitivity of preoperative imaging of tumors before 1994 was 75%, compared with 98% after this period, which included use of endoscopic ultrasound scanning (P = 0.012). A combination of palpation and intraoperative ultrasound detected 92% of tumors. Distal pancreatectomy (40%), enucleation (34%), and pancreaticoduodenectomy (16%) were the most common procedures and pancreatic fistula occurred in 18% of patients. Three patients underwent noncurative distal pancreatectomy in the early period. The 10-year disease-specific and disease-free survival was 100% and 90% respectively. There were 5 patients with disease recurrence. Lymph node metastases (P < 0.001), lymphovascular invasion (P < 0.001), and the presence of MEN-1 (P = 0.035) were prognostically significant adverse factors in disease-free survival. Lymphovascular invasion was the only significant factor on multivariate analysis (P = 0.002).

CONCLUSION

Pancreatic insulinomas can be readily localized preoperatively with modern imaging to avoid unsuccessful blind pancreatic resection. Surgical resection is associated with low morbidity and mortality and achieves long-term disease-free survival in the absence of lymphovascular invasion.

Intra-operative quick insulin assay to confirm complete resection of insulinomas guided by selective arterial calcium injection (SACI)

BACKGROUND AND AIMS

Insulinomas are rare endocrine disorders. Pre-operatively, conventional imaging techniques often fail to localise the tumor. In addition, due to the lack of quick insulin assays, intra-operative confirmation of complete resection was impossible until recently.

MATERIALS AND METHODS

Six patients with biochemical evidence of an insulinoma underwent pre-operative localisation studies and selective arterial calcium injection (SACI). In addition, insulin was measured before surgery and every 10-15 min after resection of the tumor using a quick insulin assay.

RESULTS

Pre-operative localisation studies identified the tumor correctly as follows: endosonography: three of four, magnetic resonance imaging: two of four and SACI: six of six. Tumors in the head and body were enucleated while those in the tail were resected (n = 2, each). Those three patients, in whom magnetic resonance imaging and/or endosonography could localise the tumors pre-operatively, underwent laparoscopic surgery while the remaining three patients underwent open surgery. Intra-operatively, insulin dropped to normal levels within 20 min in all cases. After a follow-up of 0.8-3 years, all patients remained biochemically cured.

CONCLUSIONS

Pre-operatively, SACI appears to be a very sensitive localisation technique and may be most helpful in guiding the surgeon if conventional imaging techniques fail to localise the tumor. Complete removal of an insulinoma can be reliably predicted using a quick insulin assay.