Insulinoma or non-insulinoma pancreatogenous hypoglycemia? A diagnostic dilemma

Abstract

Insulinoma is the most common cause of endogenous hyperinsulinemic hypoglycemia in adults. An alternate etiology, non-insulinoma pancreatogenous hypoglycemia (NIPH), is rare. Clinically, NIPH is characterized by postprandial hyperinsulinemic hypoglycemia, negative 72-h fasts, negative preoperative localization studies for insulinoma and positive selective arterial calcium infusion tests. Histologically, diffuse islet hyperplasia with increased number and size of islet cells is present and confirms the diagnosis. Differentiating NIPH from occult insulinoma preoperatively is challenging. Partial pancreatectomy is the procedure of choice; however, recurrence of symptoms, although less debilitating, occurs commonly. Medical management with diazoxide, verapamil and octreotide can be used for persistent symptoms. Ultimately, near-total or total pancreatectomy may be necessary. We report a case of a 67-year-old male with hypoglycemia in whom preoperative workup, including computerized tomography abdomen, suggested insulinoma, but whose final diagnosis on pathology was NIPH instead.

Endogenous hyperinsulinemic hypoglycemia: case series and literature review

“…Insulinoma is an insulin-secreting tumor, which is the most common cause of EHH in adults [4]. The majority of cases are benign, solitary, small, and intrapancreatic [5].…”

Imaging of pancreatic neuroendocrine tumors: recent advances, current status, and controversies

“…This method has high sensitivity varying from 72–100%, with most studies reporting a sentivity of 88–100% [29,32–34]. In the diagnosis of endogenous hyperinsulinemic hypoglycemia it is important to differentiate insulinoma from the noninsulinoma pancreatogenous hypoglycemia syndrome(NIPHS), which is due to nesidioblastosis, as they are treated differently[35,196,205]. Unfortunately, the cross-sectional imaging may be negative in both, 68 Ga-DOTA-SSA PET/CT can give a false positive result in NIPHS suggesting insulinoma, and the selective calcium infusion with insulin gradients can be positive in both[35,205,206].…”

“…In the diagnosis of endogenous hyperinsulinemic hypoglycemia it is important to differentiate insulinoma from the noninsulinoma pancreatogenous hypoglycemia syndrome(NIPHS), which is due to nesidioblastosis, as they are treated differently[35,196,205]. Unfortunately, the cross-sectional imaging may be negative in both, 68 Ga-DOTA-SSA PET/CT can give a false positive result in NIPHS suggesting insulinoma, and the selective calcium infusion with insulin gradients can be positive in both[35,205,206]. In a recent study [35] the results of the selective arterial calcium study with hepatic venous sampling for insulin(SACST) was reported to differentiate these two conditions using two criteria[a maximum increase in hepatic venous insulin concentration >91.5 or >263.5 ulU/mL] with 95% and 100% specificity, respectively.…”

Who stole the sugar? Recurrent hypoglycemia in three women

“…This disease leads to episodes of hypoglycemia during fasting and after physical activity. It is most commonly diagnosed in adults [16]. Historically the oldest criteria of insulinoma were described as Whipple's triad: symptoms consistent with hypoglycemia, a low plasma glucose concentration and relief of those symptoms after the plasma glucose level is raised [17].…”