An eight-week old infant with congenital hyperinsulinism has been stabilized and worked up including a PET-CT scan using 18-fluoro L-DOPA which suggests a focal lesion in the head of the pancreas. At exploration, you identify a large abnormal area in the head of the pancreas that has irregular borders and is slightly reddish in color. Biopsies with frozen sections suggest this to be a focal area of adenomatous islet cell hyperplasia with proliferation of islet cells and large nuclei. For this patient with congenital hyperinsulinism, the next best step in with management is

 

A pancreaticoduodenectomy (Whipple) operation.

 

B subtotal pancreatectomy (50 to 75%).

 

C pancreatic head resection with Roux en Y pancreaticojejunostomy.

 

D near total pancreatectomy (95 to 98%).

 

E limited resection of localized lesion.​

E limited resection of localized lesion.​ zz0.ji2qo6fcpzz

E limited resection of localized lesson.

C

correct answer

C pancreatic head resection with Roux en Y pancreaticojejunostomy

 

Congenital hyperinsulinism (HI) is the most common cause of persistent hypoglycemia in neonates. Early signs of hypoglycemia include tremulousness, irritability, tachycardia, sweating and cyanosis. Profound hypoglycemia may lead to seizures. Recurrent seizures due to persistent hypoglycemia will lead to permanent brain damage.

 

Congenital hyperinsulinism may be due to diffuse involvement of the pancreatic Beta cells (diffuse HI) or from focal adenomatous islet cell hyperplasia (focal HI). The most common mutations leading to focal or diffuse HI involve ABCC8 or KCNJ11 genes; both genes encode the Beta cell ATP-dependent potassium channel (KATP). A genetic work up is imperative as knowledge of the specific mutation will aid in determining the potential response to medical management and the extent of the disease (i.e. diffuse versus focal).

 

Distinguishing between these two variations is important for surgical treatment. Focal HI should be treated by selective partial pancreatectomy, without high risk of postoperative diabetes, while diffuse HI should be treated with near total pancreatectomy, which has a significant long term risk of diabetes. The 18-fluoroDOPA PET/CT scan is the diagnostic procedure of choice to help localize focal lesions. Conventional imaging techniques such as ultrasound, CT scan, and MRI have been unreliable and unsuccessful in localizing focal lesions.

 

At exploration, the pancreas should be carefully inspected starting with the portion of the pancreas that correlates with the F-DOPA scan findings. Focal lesions will often have a slightly different appearance in color (reddish or marble) or texture (more firm) compared to the rest of the pancreas. Intraoperative US may aid in identifying the focal lesion if it cannot be identified visually or by palpation. If no focal lesion is identified, then random biopsies should be taken from the head, body and tail to rule out diffuse HI. Small superficial lesions may be sharply excised whereas larger lesions require a partial pancreatectomy. Given the size and location of this lesion, pancreatic head resection with Roux-en-Y pancreaticojejunostomy drainage is the treatment of choice. Rarely a focal head lesion extending into the duodenum requires a Whipple procedure. A very limited resection of a focal lesion should be avoided because these lesions can have irregular “octopus-like tentacles” that make margins difficult to define. Furthermore, clear margins should be confirmed with a frozen section prior to completing the operation.

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