Adult-Onset Focal Nesidioblastosis With Nodular Formation Mimicking Insulinoma

Diagnosis of pancreatic focal nesidioblastosis assisted by dual‑nuclide tracer positron emission tomography/computed tomography: A case report

Nesidioblastosis is a rare cause of hyperinsulinemic hypoglycemia in adults and its clinical features are similar to those of insulinoma with recurrent hypoglycemic attacks. The present study reports the case of a 48-year-old man who visited the Affiliated Hospital of Zunyi Medical University (Zunyi, China) with a 5-year history of recurrent hypoglycemic symptoms such as dizziness and palpitations. Abdominal magnetic resonance imaging (MRI) showed a mass of ~1.2x1.0 cm in the head of the pancreas, which was suspected to be an insulinoma. For confirmation, the patient underwent both fluorine-18-fluorodeoxyglucose (18F-FDG) and gallium-68-labeled 1,4,7,10-tetraazacyclododecane-1,4,7,10-teraacetic acid-d-Phel-Tyr3-Thr8-OC (68Ga-DOTATATE) positron emission tomography/computed tomography (PET/CT), which showed a moderately increased uptake of 18F-FDG but no uptake of 68Ga-DOTATATE in the corresponding lesion. The patient subsequently underwent surgery to remove the lesion, which was pathologically confirmed as a pancreatic nesidioblastosis. This case showed that nesidioblastosis should be considered a differential diagnosis for insulinoma and that dual nuclear tracer PET/CT imaging is helpful for differentiating between the two. If conventional imaging techniques such as ultrasound, CT and MRI cannot identify the cause of hypoglycemia in future cases, dual-nuclide tracer PET/CT imaging should be considered.

Nesidioblastosis and Subsequent Diabetes Mellitus in a Dog with Hyperinsulinemic Hypoglycemia Treated with Partial Pancreatectomy

A 6.5 yr old castrated male mixed-breed dog was presented for clinical signs associated with hypoglycemia. Hyperinsulinemic hypoglycemia was diagnosed as the cause of the persistent hypoglycemia. No obvious pancreatic mass was seen on abdominal computed tomography and exploratory laparotomy. A partial pancreatectomy was performed with the suspicion of an insulinoma-causing hyperinsulinemic hypoglycemia. Nesidioblastosis was diagnosed based clinical, biochemical, and histopathologic findings. There was beta cell hyperplasia and no evidence of neoplasia. The dog was euglycemic postoperatively after a partial pancreatectomy. Long-term follow-up after 2 yr revealed that the dog was diagnosed with diabetes mellitus.

Non-insulinoma pancreatogenous hypoglycemia syndrome (NIPHS)/Nesidioblastosis as the underlying cause of recurrent hypoglycemia in a diabetic adult

Non-insulinoma pancreatogenous hypoglycemia syndrome (NIPHS), without previous bariatric surgery, is a rare form of hypoglycemia in adult patients and is associated with nesidioblastosis. Adult-onset nesidioblastosis in diabetic patients is rare and histologically identical to "non-insulinoma pancreatogenous hypoglycemia syndrome (NIPHS)". Nesidioblastosis is rare in adults and clinically and biochemically mimics Insulinoma. In the literature, there have only been four cases of adult nesidioblastosis that followed diabetes mellitus. We report a case of nesidioblastosis in a 36-year-old diabetic female presenting with dizziness, sweating, and palpitations for three years. Selective non-invasive techniques failed to detect a tumor. Based on the pursuit of an insulinoma, a distal pancreatectomy specimen was received at our laboratory, and a diagnosis of nesidioblastosis was made. She is currently on follow-up with a favorable outcome. The definitive diagnosis of nesidioblastosis is made on a histological basis. The preferred form of treatment is pancreatic surgical resection. Nesidioblastosis should be taken into consideration in cases where diabetes transforms into hyperinsulinemic hypoglycemia.

Circularity of islets is a distinct marker for the pathological diagnosis of adult non-neoplastic hyperinsulinemic hypoglycemia using surgical specimens

BACKGROUND

Adult non-neoplastic hyperinsulinemic hypoglycemia (ANHH), also known as adult-onset nesidioblastosis, is a rare cause of endogenous hyperinsulinemic hypoglycemia in adults. This disease is characterized by diffuse hyperplasia of pancreatic endocrine cells and is diagnosed by a pathological examination. While diagnostic criteria for this disease have already been proposed, we established more quantitative criteria for evaluating islet morphology.

METHODS

We measured the number, maximum diameter, total area, and circularity (representing how closely islets resemble perfect spheres) of islets contained in representative sections of ANHH (n = 4) and control cases (n = 5) using the NIS-Elements software program. We also measured the average cell size, percentage of cells with enlarged nuclei, and percentage of cells with recognizable nucleoli for each of three representative islets. We also assessed the interobserver diagnostic concordance of ANHH between five experienced and seven less-experienced pathologists.

RESULTS

There was no significant difference in the number, maximum diameter, or total area of islets between the two groups, even after correcting for these parameters per unit area. However, the number of islets with low circularity (< 0.71) per total area of the pancreatic parenchyma was significantly larger in ANHH specimens than in controls. We also found that the percentage of cells with recognizable nucleoli was significantly higher in the ANHH group than in the controls. There were no significant differences in the average cell size or the number of cells with enlarged nuclei between the groups. The correct diagnosis rate with the blind test was 47.5% ± 6.12% for experienced pathologists and 50.0% ± 8.63% for less-experienced pathologists, with no significant differences noted.

CONCLUSIONS

Low circularity, which indicates an irregular islet shape, referred to as "irregular shape and occasional enlargement of islets" and "lobulated islet structure" in a previous report, is a useful marker for diagnosing ANHH. An increased percentage of recognizable nucleoli, corresponding to "macronucleoli in β-cells," has potential diagnostic value.

Diffuse, Adult-Onset Nesidioblastosis/Non-Insulinoma Pancreatogenous Hypoglycemia Syndrome (NIPHS): Review of the Literature of a Rare Cause of Hyperinsulinemic Hypoglycemia

Differential diagnosis of hypoglycemia in the non-diabetic adult patient is complex and comprises various diseases, including endogenous hyperinsulinism caused by functional β-cell disorders. The latter is also designated as nesidioblastosis or non-insulinoma pancreatogenous hypoglycemia syndrome (NIPHS). Clinically, this rare disease presents with unspecific adrenergic and neuroglycopenic symptoms and is, therefore, often overlooked. A combination of careful clinical assessment, oral glucose tolerance testing, 72 h fasting, sectional and functional imaging, and invasive insulin measurements can lead to the correct diagnosis. Due to a lack of a pathophysiological understanding of the condition, conservative treatment options are limited and mostly ineffective. Therefore, nearly all patients currently undergo surgical resection of parts or the entire pancreas. Consequently, apart from faster diagnosis, more elaborate and less invasive treatment options are needed to relieve the patients from the dangerous and devastating symptoms. Based on a case of a 23-year-old man presenting with this disease in our department, we performed an extensive review of the medical literature dealing with this condition and herein presented a comprehensive discussion of this interesting disease, including all aspects from epidemiology to therapy.

Hyperinsulinemic hypoglycemia in adolescents: case report and systematic review

Background

Hyperinsulinemic hypoglycemia is the most common cause of severe and persistent hypoglycemia in neonates and children. It is a heterogeneous condition with dysregulated insulin secretion, which persists in the presence of low blood glucose levels.

Case presentation

We report a case of a 15 year-old male with hyperinsulinemic hypoglycemia, who underwent a subtotal pancreatectomy after inadequate response to medical therapy. Pathological examination was positive for nesidioblastosis (diffuse β-cell hyperplasia by H-E and immunohistochemical techniques). The patient’s blood glucose levels normalized after surgery and he remains asymptomatic after 1 year of follow-up. The systematic review allowed us to identify 41 adolescents from a total of 205 cases reported in 22 manuscripts, from a total of 454 found in the original search done in PubMed and Lilacs.

Conclusions

Although very well reported in children, hyperinsulinemic hypoglycemia can occur in adolescents or young adults, as it happens in our reported case. These patients can be seen, treated and reported by pediatricians or adult teams either way due to the wide age range used to define adolescence. Most of them do not respond to medical treatment, and subtotal distal pancreatectomy has become the elected procedure with excellent long-term response in the vast majority.