Vol.2, No.1, 20-23 (2010)
Copyright © 2010 http://www.scirp.org/journal/HEALTH/
Openly accessible at
Does conventional abdominal preoperative
ultrasonography have a role in the detection of
pancreatic insulinoma? A case report
L. Spadaro, O. Magliocco, G. Trovato, F. Purrello
Dpt di Medicina Interna e Medicina Specialistica, Università degli Studi di Catania, Ospedale Garibaldi, Italy; fpurrell@unict.it
Received 2 September 2009; revised 14 October 2009; accepted 16 October 2009.
Combinations of strategies as MRI, endoscopic
sonography, selective arteriography, were the
first choice for the detection of pancreatic insu-
linoma. In these proposal, therefore, abdominal
was not in- cluded at all. Case presentation: a
78-year-old no diabetic women was referred to
us because fasting hypoglycemic symptoms.
The clinical and laboratory findings suggested
an insulinoma. Abdominal ultrasound showed a
small solid mass in the head-istmus pancreatic
tract. Conclusion: the solid mass was confirmed
with a contrast-enhanced- computed tomogra-
phy of the abdomen. A surgical enucleation of
the tumor was achieved by laparoscopy and
histological examination of the specimen estab-
lished a diagnosis of insulinoma. This case re-
inforced the value of the conventional trans-
abdomen ultrasound in addition to accuracy of
anamneses and biochemical tests as the first
step in the hospital clinical setting for man-
agement of pancreatic insulinoma, reserving as
the second step more expensive and invasive-
ness techniques.
Keywords: Lunch Time Napping;
Mental Work Efficiency
Insulinomas are rare endocrine tumors of the pancreas.
Their incidence was estimated to be four cases per 1
million person-years [1]. In the earliest stages of the tu-
mor’s clinical history, they usually manifest because of
hypersecretion of insulin, responsible for the typical
hypoglycemic symptoms. The three criteria (Whipple's
triad or Whipple's criteria) on which hypoglycemia due
to pancreatic islet-cell disease (most commonly insuli-
noma) is diagnosed are: 1) symptoms known or likely to
be caused by hypoglycemia, 2) low blood glucose levels
associated with clinical signs, and 3) reversal of clinical
signs with the administration of glucose. The optimal
therapy is curative surgical removal of the tumor. There-
fore, preoperative localization of the lesion is crucial for
determining the proper surgical treatment. However, in
several cases, insulinoma identification remains ex-
tremely difficult and there was a continuing debate on
the optimal strategy for his localization. Some authors
have proposed MR as the first choice for preoperative
imaging [2,3], whereas recent reports suggested a com-
bined imaging protocol that consists of both dual-phase
thin-section multi-detector CT and endoscopic sonogra-
phy [4,5]. Actually, conventional abdominal ultrasono-
graphy was not included in the imaging protocol due to
his limited successful reports. We wish to present our
own experience with abdominal conventional ultrasound
in a case of insulinoma.
A non-diabetic 78-year-old woman was brought to our
attention because of hypoglycaemic symptoms. The pa-
tient had a history of mild and transient sweating, anxi-
ety and trembling recurring for about 2 years during her
activities of ordinary life. These symptoms usually dis-
appeared after food ingestion. Ten days before her refer-
ral to our hospital, she had a more severe episode with
sweating, trembling, anxiety, palpitations, nausea, dizzi-
ness with tiredness and a severe headache crisis. She had
been seen by her family physician. The practitioner had
ordered general blood tests that had revealed low serum
glucose level (2.2 mmol/L, 40 mg/dL). Therefore, he
suggested the admission to the hospital, to determine the
cause of hypoglycaemia.
She had a history of hypertension and dyslipidemia on
pharmacological treatment. She didn’t have any treat-
ment or drugs that might have induced hypoglycaemia.
On admission to our hospital, on examination, the pa-
tient was overweight; her height was 165 cm and body
weight 94,5 Kg, BMI 34,74, CV 118 cm. Blood pressure
was 140/80 mmHg and the pulse was 68. Neurological
examination and an electrocardiogram were normal.
Laboratory tests were performed: urinalysis, blood cell
counts, and biochemical tests (e.g. the liver and kidney
function tests) other than plasma glucose concentration
L. Spadaro et al. / Health 2 (2010) 20-23
SciRes Copyright © 2010 http://www.scirp.org/journal/HEALTH/Openly accessible at
were unremarkable.
On the second hospital day, we performed the super-
vised 72-Hour Fast. At the 12th hour, the patient showed
pallor, sweating, trembling, tiredness, nervousness and
confusion. The plasma glucose level was 42 mg/dl.
Therefore, we stopped the test through correction of the
low glucose level by food ingestion with rapid relieving
of the symptoms (“Whipple’s triad”) (Table 1). Plasma
insulin levels during the test were also shown in Table 1.
These data supported the diagnostic suspect of insuli-
As a first attempt to locate it, an abdominal ultrasono-
graphy of the pancreas was performed with a 3.5 MHz
probe mechanical real time sector scanner (Logiq 500).
Patient was examined in a semierect position after fast-
ing for 12 hours. Scans of the head, body, and tail of the
pancreas were obtained in both transverse and longitu-
dinal planes without respiratory maneuvers, by using the
fluid-filled stomach as an acoustic window. The exami-
nation showed a 12,4 mm x 13,7 mm hypoechoic solid
mass, with the echo texture finer in relation to surround-
ing pancreatic tissue, localized in the head-isthmus pan-
creatic tract, without dilatation of the Wirsung’s duct.
(Figure 1, left). A contrast-enhanced computed tomo-
graphy of the abdomen was then performed. The patient
was scanned in suspended respiration, following the oral
administration of contrast material to visualize the small
bowel. Pre-contrast abdominal scans CT, revealed the
presence of a protrusion of the pancreatic contour in the
head-isthmus pancreatic tract, but itself is non-specific.
After the bolus injection of contrast material and rapid
sequential scanning, a transient increase in contrast en-
hancement (tumor blush) in the surrounding pancreatic
tissue was observed, confirming an area of increased
density of 1,5 cm (Figure 1, right). One month later, a
surgical enucleation of the tumor was achieved by
Table 1. 72-Hour fast (date onset of the fast was the last inges-
tion of calories, 12 hours before the first measurement; all of
the non essential medications were stopped; no assumption of
caffeine or tobaccos).
Time Symptoms
or signs Glucose Insulin c-peptide
p.m. none 48
p.m. none 59
p.m. none 64
p.m. none 62
a.m none 69
a.m. none 53
Whipple’s triad:
end of the fast
laparoscopy, which was performed initially to confirm
by direct view the presence of the small nodule on the
surface of the pancreatic; its enucleation was then car-
ried out. Histological examination of the specimen es-
tablished a diagnosis of an endocrine tumour of the pan-
creas compatible with an insulinoma, confirmed by the
presence of insulin secretory granules. The patient’s
clinical symptoms completely disappeared.
Endocrine tumors of the pancreas originate from mul-
tipotential stem cells that have retained the capacity to
proliferate and differentiate themselves in the various
cellular lines that make up this group of neoplasms. In-
sulinomas represent the most frequently found function-
ing endocrine tumors of the pancreas and, in most cases,
are benign (85%-99%), single (93%-98%) and less than
Figure 1. Imaging studies of the pancreatic lesion. Ultrasound (left) and CT (right) technique show the characteristic mass of the
pancreas (arrows).
L. Spadaro et al. / HEALTH 2 (2010) 20-23
SciRes Copyright © 2010 http://www.scirp.org/journal/HEALTH/Openly accessible at
2.5 cm in diameter [6,7]. Age of onset is usually 40-60
years, ranging from 6 weeks to 70 years. No sex differ-
ence has been reported [8]. In our case, the patient was a
78-year-old female.
Insulinoma become clinically evident because of signs
and symptoms linked to hypoglycemia due to the hyper-
secretion of insulin. The symptoms of hypoglycemia
arise from the autonomic nervous system and from an
insufficient supply of glucose to the brain (neuroglyco-
penia). During acute insulin-induced hypoglycemia in
healthy persons, symptoms have been recognized at
plasma glucose levels of approximately 60 mg per deci-
liter as measured in arterialized venous blood, and im-
pairment of brain function has occurred at approximately
50 mg per deciliter [9-10-11]. In our patient, the first
report of low plasma glucose levels (40 mg/dL) was as-
sociated with typical hypoglycemic symptoms, sweating,
trembling, anxiety, palpitations, nausea, dizziness with
tiredness and headache crisis. Moreover, her past history
was positive for sporadic and vague symptoms, recurring
for about 2 years, but no plasma glucose levels was
measured before. It has been reported that the time in-
terval from the onset of symptoms to diagnosis ranges
from 10 days to 30 years (median 2 years), and that the
hypoglycemic episodes may happen at irregular intervals
with a varying duration [8].
The symptoms intermittency and the multifaceted
characters delay the diagnosis, although all signs and
symptoms are usually reverted rapidly by oral or par-
enteral glucose administration. Obesity or weight gain is
present in 25% of patients, justified, at least in part, by
the need for frequent feeding. Accordingly, our patient
was overweight, and she reported a weight gain (over 20
kg) in the past two years. Because of the lack of speci-
ficity of the symptoms, it is necessary to measure a low
glucose level at the time that the spontaneous symptoms
occur and that the symptoms are relieved through cor-
rection of the low glucose level (“Whipple’s triad”) be-
fore concluding that the patient have a hypoglycemic
disorder. The supervised 72-hour fast is the classic di-
agnostic test for hypoglycemia. In our case, the super-
vised 72-hour fast confirmed a hypoglycemic disorder.
In addition, the appearance of the Whipple’s triad asso-
ciated with plasma glucose level 45 mg/dl, insulin
level 6 /mL and c-peptide level 0.2 mmol/L sug-
gested the diagnosis of insulinoma [12].
When the diagnosis of pancreatic insulinoma has been
established clinically and biochemically, the precise lo-
calization of the tumor is crucial, to facilitate the surgical
resection and to prevent a blind partial or subtotal pan-
createctomy [13]. Insulinomas are usually small and
difficult to detect. The main problem in detecting a pan-
creatic insulinoma lies in the organ’s anatomic structure
and the tumor’s small dimensions at clinical appearance.
Most of the tumors are in the body-tail area of the pan-
creas and are less than 2 cm in diameter [14]. Many
procedures have been proposed for their localization.
These imaging techniques vary in accuracy, invasiveness,
operator dependence, and cost. Recent protocols propose
the combination of advanced imaging techniques as well
as MRI, endoscopic sonography, and CT as the first
choice for preoperative detection of insulinomas [2,4]. In
these proposals, therefore, abdominal ultrasonography is
not included at all. However, ultrasonography is a non-
invasive and relatively inexpensive technique, and actu-
ally it is easily available everywhere. In the case report
we discuss here, we performed abdominal ultrasonogra-
phy as the imaging technique of first choice because it
was immediately available in our unit. In our patient,
this technique correctly localized a pancreatic solid mass
as a well-defined, hypoechoic lesion, without calcifica-
tions or necrosis. This finding was then confirmed by CT
Early studies of preoperative ultrasound localization
primarily used static scanners, yielding disappointing
results. More recently, a higher sensitivity (approxi-
mately 60-80%) has been reported using real-time US
equipment [7,15,16]. This level of accuracy was highly
dependent on meticulous attention to scanning technique
[6]. Ultrasonographic detection of insulinomas was dif-
ficult because of the frequent location at the body-tail
area of the pancreas and the small sizes of the tumours in
generally obese patients. In our patient insulinoma was
small, < 1.5 cm, and was localized in head-isthmus pan-
creatis tract. It is important to emphasize the improve-
ment in ultrasonographic technology in terms of spatial
resolution with increased diagnostic sensitivity and ac-
curacy. In addition, ultrasonography technique enabled
us to view continuous images of the lesion from several
angles, with relative ease compared to other imaging
In the current case, after correct diagnosis and local-
ization of pancreatic insulinoma, surgical resection was
performed successfully and without complication. Actu-
ally, after one year, the patient was free from symptoms.
In conclusion, the present case supported the value of
the conventional abdomen ultrasonography as the first
step in the preoperative localization of pancreatic insu-
linomas, reserving as the second step more expensive
and invasiveness techniques.
[1] Service, F.J., McMahon, M.M., O’Brien, P.C., et al.
(1991) Functioning insulinoma: incidence, recurrence,
and long term survival of patients: a 60-years study.
Mayo Clin Proc, 66, 711-719.
[2] Virally, M.L., Guillausseau, P.J. (1999) Hypoglycemia in
adults. Diabetes e Metabolism, 25, 477-490.
L. Spadaro et al. / Health 2 (2010) 20-23
SciRes Copyright © 2010 http://www.scirp.org/journal/HEALTH/Openly accessible at
[3] Catalano, C., Pavone, P., Laghi, A., et al. (1999) Local-
ization of pancreatic insulinomas with MR imaging at 0.5
T. Acta Radiol, 39, 644-648.
[4] Moore, N.R., Rogers, C.E., Britton, B.J. (1995) Magnetic
resonance imaging of endocrine tumors of the pancreas.
Br J Radiol, 68, 341-347.
[5] Gouya, H., Vignaux, O., Augui, J., Dousset, B., Palazzo,
L., Louvel, A., Chaussade, S., Legmann, P. (2003) CT,
endoscopic sonography, and a combined protocol for
preoperative evaluation of pancreatic insulinomas. AJR,
181, 987-992.
[6] Schumacher, B., Lubke, H.J., Frieling, T., Strohmeyer, G.,
Starke, A.A. (1996) Prospective study on the detection of
insulinomas by endoscopic ultrasonography. Endo scopy,
28, 273-276.
[7] Liu, T.H., Tseng, H.C., Zhu, Y., Zhong, S.X., Chen, J.,
Cui, Q.C. (1985) Insulinoma: an immunohistochemical
and morphologic analysis of 95 cases. Cancer, 56,
[8] Stefanini, P., Carboni, M., Patrassi, N., Basoli, A. (1974)
Beta islet-cell tumors of the pancreas: result of a study on
1067 cases. Surgery, 75, 597-609.
[9] Villary, M.L., Guillausseau, P.J. (1999) Review:
Hypoglycemia in adults. Diabetes & Metabolism, 25,
[10] Schwartz, N.S., Clutter, W.E., Shah, S.D., Cryer, P.E.
(1987) Glycemic thresholds for activation of glucose
counterregulatory systems are highter than the threshold
for symptoms. J Clin Invest, 79, 777-781.
[11] Mitrakou, A., Ryan, C., Veneman, T., et al. (1991) Hier-
rarchy of glycemic thresholds counterregulatory hormone
secretion, symptoms, and cerebral dysfunction. Am J
Physiol, 260, E67-E74.
[12] Cyper, P.E. (1993) Glucose counterregulation: the
physiological mechanisms that prevent or correct
hypoglycaemia. In: Frier, B.M., Fisher, B.M., (eds.),
Hypoglycaemia and Diabetes: Clinical and
Physiological Aspects. Edward Arnold, London, 34-55.
[13] Service, F.J. (1995) Review: Hypoglycemic disorders..
NEJM, 332, 1144-1152.
[14] Placzkowski, K.A., Vella, A., Thompson, G.B., Grant,
C.S., Reading, C.C., Charboneau, J.W., Andrews, J.C.,
Lloyd, R.V., Service, F.J. (2009) Secular trends in the
presentation an management of functioning insulinoma at
the majp clinic, 1987-2007. J Clin Endocrinol Metab.
[15] D’Onofrio, M., Mansueto, G., Vasori, S., Falconi, M.,
Procacci, C. (2003) Contrast-enhanced ultrasonographic
detection of small pancreatic insulinoma. J Ultrasound
Med, 22, 413- 417.
[16] Angeli, E., vanzulli, A., Castrucci, M., Venturini, M.,
Sironi, S., Zerbi, A., Di Carlo, V., Del Maschio, A. (1997)
Value of abdominal sonography and MR imaging at 0.5 T
in preoperative detection of pancreatic insulinoma: a
comparison with dynamic CT and angiography. Abdom
Imaging, 22(3), 295-303.
[17] Galiber, A.K., Reading, C.C., Charboneau, J.W., Sheedy,
P.F., James, E.M., Gorman, B., Grant, C.S., van Heerden,
J.A., Telander, R.L. (1998) Localization of pancreatic
insulinoma: comparison of pre-and intraoperative US
with CT and angiography. Radiology, 166(2), 405-8.