J Clin Ultrasound 20:615-617, November/December 1992 CCC 0091-2751/92/090615-03 Q 1992 by John Wiley & Sons, Inc.
Case Report
Insulinorna: Detection by Intraoperative Ultrasonography T. C. Brightbill, MD, E. 0. Templeton, MD, FACR, David Sperling, MD, and Laslie P. Mooney, BS, RT, RDMS
Insulinoma is a rare pancreatic islet cell tumor with an annual incidence of 1 in 1.25 million people in the United States.' Many imaging modalities, invasive and noninvasive, have been used for localization of these neoplasms. For many years, pancreatic arteriography has been the localization procedure of choice when the findings from noninvasive imaging such as U1trasonography, computed tomography (CT), or magnetic resonance imaging (MRI) are negative or equivocal. We describe a case of an insulinFrom The Department of Radiology, Baptist Medical Center Montclair, Birmingham, Alabama. For reprints contact T. C. Brightbill, MD, Department of Radiology, BMCM, 800 Montclair Road, Birmingham, Alabama 35213.
oma detected by intraoperative ultrasonography following localization with an arterial stimulation venous sampling technique.2 CASE REPORT
A 73-year-old white woman complained of a 7-month history of episodes of confusion and paranoia. Routine blood chemistries revealed a serum glucose of 25. The patient was evaluated by an endocrinologist and was noted to have fasting blood sugars in the range of 27 to 60. The patient was suspected of having insulinoma. However, a CT, MRI, and pancreatic arteriogram were negative. Selective arterial stimulation with venous sampling using calcium gluconate
FIGURE 1. Arterial stimulation venous sampling (ASVS): Insulin levels after calcium infusion.
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CASE REPORT: BRIGHTBILL ET AL.
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FIGURE 2. lntraoperative ultrasonography of insulinoma.
FIGURE 3. Gross specimen of insulinoma
as an insulin secretagogue was then performed.2 Arterial injections were made in the superior mesenteric artery (which gave rise to the hepatic artery), splenic artery, and celiac artery. Venous samples were obtained from the right and left hepatic veins at selected time intervals up to 2 minutes. Given the elevated insulin level in the hepatic arteryhight hepatic vein sample, the results suggested a tumor in the pancreatic head (Figure 1). The patient subsequently underwent laparotomy. Intraoperative ultrasonography detected the 1.0-cm mass, which was firm and nonencapsulated, in the pancreatic head representing an insulinoma (Figure 2). The tumor was enucleated (Figure 3) and the patient experienced an unremarkable postoperative course, with blood sugars returning to normal. DISCUSSION
Insulinomas are the most common islet cell tumor of the pancreas3 These tumors are usually
small, 70% being smaller than 1.5 cm.' Despite numerous imaging modalities, these masses remain undetected in 10% to 20% of patient^.^ Although controversial, a blind distal pancreatectomy is an alternative for treating patients with unlocalized lesions. However, this procedure carries significant morbidity, and insulinomas are distributed throughout the pancreatic head (28% to 35%), body (30% to 40%), and tail (23% t o 34%) in nearly equal fashion.' Ultrasonography is an ideal preoperative procedure for localization because it is noninvasive and inexpensive. However, it has been reported to have a sensitivity only in the range of 50% to 60%.4-6 The sensitivity of CT is reported to be 40% to 60% as well. Pancreatic arteriography has had an accuracy as high as 85% in localizing insulinomas.2 In the last several years this rate has declined, and a greater number of tumors go undetected with negative imaging studies. In one study, the use of multiple preoperative procedures, including portal venous sampling, were successful in only 62%of patient^.^ Since its introduction in 1982, intraoperative ultrasonography has become increasingly popular in localizing occult insulinomas. This procedure produces excellent results due to lack of overlying soft tissues and gas, and has been reported to detect tumors at surgery that were not palpable. The best clinical results are seen with a combination of intraoperative ultrasonography and palpation by an experienced urgeo on.',^,^ Several studies have also advocated the usefulness of ultrasonography for determining the relationship of the tumor to the pancreatic duct, bile ducts, and portal We described a case of intraoperative detection of an occult insulinoma following localization with an arterial stimulation venous sampling technique, and we recommend intraoperative ultrasonography as JOURNAL OF CLINICAL ULTRASOUND
INSULINOMA
the procedure of choice in detecting these lesions.
REFERENCES 1. Functional endocrine tumors of the pancreas: Clinical presentation, diagnosis, and treatment: Curr Prob Surg 1990,309-345. 2. Doppman J, Miller D, et al: Insulinomas: Localization with selective intraarterial injection of calcium. Radiology 178:237-241, 1991. 3. Norton J, Shawter T, Doppman J, et al: Localization and surgical treatment of occult insulinomas. Ann Surg 212:615-620, 1990.
VOL. 20, NO. 9, NOVEMBERlDECEMBER 1992
617
4. Grant C, Hurden J, et al: Insulinomas. Arch Surg 123~843-848, 1988. 5. Boden G Glucagonomas and insulinomas. Gastrointest Endocrinol 18:831-845, 1989. 6. Galiber A, Reading C, et al: Localization of pancreatic insulinoma: Comparison of pre and intraoperative US with CT and angiography. Radiology 166:405-408, 1988. 7. Proye C, Boissel P: Preoperative imaging versus intraoperative localization of tumors in adult surgical patients with hyperinsulinemia: A multicenter study of 338 patients. World J Surg 12:685-690, 1988.
Case Report
Insulinorna: Detection by Intraoperative Ultrasonography T. C. Brightbill, MD, E. 0. Templeton, MD, FACR, David Sperling, MD, and Laslie P. Mooney, BS, RT, RDMS
Insulinoma is a rare pancreatic islet cell tumor with an annual incidence of 1 in 1.25 million people in the United States.' Many imaging modalities, invasive and noninvasive, have been used for localization of these neoplasms. For many years, pancreatic arteriography has been the localization procedure of choice when the findings from noninvasive imaging such as U1trasonography, computed tomography (CT), or magnetic resonance imaging (MRI) are negative or equivocal. We describe a case of an insulinFrom The Department of Radiology, Baptist Medical Center Montclair, Birmingham, Alabama. For reprints contact T. C. Brightbill, MD, Department of Radiology, BMCM, 800 Montclair Road, Birmingham, Alabama 35213.
oma detected by intraoperative ultrasonography following localization with an arterial stimulation venous sampling technique.2 CASE REPORT
A 73-year-old white woman complained of a 7-month history of episodes of confusion and paranoia. Routine blood chemistries revealed a serum glucose of 25. The patient was evaluated by an endocrinologist and was noted to have fasting blood sugars in the range of 27 to 60. The patient was suspected of having insulinoma. However, a CT, MRI, and pancreatic arteriogram were negative. Selective arterial stimulation with venous sampling using calcium gluconate
FIGURE 1. Arterial stimulation venous sampling (ASVS): Insulin levels after calcium infusion.
615
CASE REPORT: BRIGHTBILL ET AL.
616
FIGURE 2. lntraoperative ultrasonography of insulinoma.
FIGURE 3. Gross specimen of insulinoma
as an insulin secretagogue was then performed.2 Arterial injections were made in the superior mesenteric artery (which gave rise to the hepatic artery), splenic artery, and celiac artery. Venous samples were obtained from the right and left hepatic veins at selected time intervals up to 2 minutes. Given the elevated insulin level in the hepatic arteryhight hepatic vein sample, the results suggested a tumor in the pancreatic head (Figure 1). The patient subsequently underwent laparotomy. Intraoperative ultrasonography detected the 1.0-cm mass, which was firm and nonencapsulated, in the pancreatic head representing an insulinoma (Figure 2). The tumor was enucleated (Figure 3) and the patient experienced an unremarkable postoperative course, with blood sugars returning to normal. DISCUSSION
Insulinomas are the most common islet cell tumor of the pancreas3 These tumors are usually
small, 70% being smaller than 1.5 cm.' Despite numerous imaging modalities, these masses remain undetected in 10% to 20% of patient^.^ Although controversial, a blind distal pancreatectomy is an alternative for treating patients with unlocalized lesions. However, this procedure carries significant morbidity, and insulinomas are distributed throughout the pancreatic head (28% to 35%), body (30% to 40%), and tail (23% t o 34%) in nearly equal fashion.' Ultrasonography is an ideal preoperative procedure for localization because it is noninvasive and inexpensive. However, it has been reported to have a sensitivity only in the range of 50% to 60%.4-6 The sensitivity of CT is reported to be 40% to 60% as well. Pancreatic arteriography has had an accuracy as high as 85% in localizing insulinomas.2 In the last several years this rate has declined, and a greater number of tumors go undetected with negative imaging studies. In one study, the use of multiple preoperative procedures, including portal venous sampling, were successful in only 62%of patient^.^ Since its introduction in 1982, intraoperative ultrasonography has become increasingly popular in localizing occult insulinomas. This procedure produces excellent results due to lack of overlying soft tissues and gas, and has been reported to detect tumors at surgery that were not palpable. The best clinical results are seen with a combination of intraoperative ultrasonography and palpation by an experienced urgeo on.',^,^ Several studies have also advocated the usefulness of ultrasonography for determining the relationship of the tumor to the pancreatic duct, bile ducts, and portal We described a case of intraoperative detection of an occult insulinoma following localization with an arterial stimulation venous sampling technique, and we recommend intraoperative ultrasonography as JOURNAL OF CLINICAL ULTRASOUND
INSULINOMA
the procedure of choice in detecting these lesions.
REFERENCES 1. Functional endocrine tumors of the pancreas: Clinical presentation, diagnosis, and treatment: Curr Prob Surg 1990,309-345. 2. Doppman J, Miller D, et al: Insulinomas: Localization with selective intraarterial injection of calcium. Radiology 178:237-241, 1991. 3. Norton J, Shawter T, Doppman J, et al: Localization and surgical treatment of occult insulinomas. Ann Surg 212:615-620, 1990.
VOL. 20, NO. 9, NOVEMBERlDECEMBER 1992
617
4. Grant C, Hurden J, et al: Insulinomas. Arch Surg 123~843-848, 1988. 5. Boden G Glucagonomas and insulinomas. Gastrointest Endocrinol 18:831-845, 1989. 6. Galiber A, Reading C, et al: Localization of pancreatic insulinoma: Comparison of pre and intraoperative US with CT and angiography. Radiology 166:405-408, 1988. 7. Proye C, Boissel P: Preoperative imaging versus intraoperative localization of tumors in adult surgical patients with hyperinsulinemia: A multicenter study of 338 patients. World J Surg 12:685-690, 1988.
