Pancreatic Neuroendocrine Neoplasms

1. Pancreatic Endocrine
Neoplasm
Lecture 30

2. Pancreatic Neuroendocrine Tumors (PanNETs)
Also known as "islet cell tumors”
Common
Insulinoma 70–75%
Gastrinoma 20–25%
Rare
VIPoma
Glucagonoma
Somatostatinoma

3. Pancreatic Endocrine Neoplasms
Only 2% of all pancreatic neoplasms
Most common in adults
Neoplasm are mostly functional but some totally nonfunctional
Benign tumor differentiated from malignant having evidence of
metastasis to lymph nodes and liver

4. Pancreatic Endocrine Neoplasms
In general, tumors less than 2 cm in size tend to behave in an indolent
manner
Benign: Approximately 90% of insulinomas are benign
Malignant: 60% to 90% of other functioning and nonfunctioning pancreatic
endocrine neoplasms tend to be malignant

5. β-cell tumors (insulinomas)
The most common , 80% of islet cell tumors may elaborate sufficient
insulin to induce clinically significant hypoglycemia
The characteristic clinical triad associated with it includes;
a. Attacks of hypoglycemia; blood glucose fall below 50 mg/dL
b. Attacks of CNS manifestations such as; confusion, stupor, and
loss of consciousness
c. Attacks precipitated by fasting or exercise and quickly relieved by
feeding or parenteral administration of glucose

6. Insulinomas
Generally benign and solitary, can be multiple
About 10% are diagnosed as carcinomas, on the evidence of
metastases
Located anywhere in pancreas often <2 cm in diameter

7. Insulinomas
Morphology:
Encapsulated, pale to red-brown tumor
nodules
Histologically; regular cords of
monotonous cells in orientation to the
vasculature, look remarkably like giant
islets
By IHC, insulin can be localized in the
tumor cells

8. Gastrinomas
Gastrinomas arise in conjunction with MEN-1 syndrome
Gastrinomas (gastrin-producing tumors ) may arise in pancreas, peri-
pancreatic region, or wall of duodenum
Over half locally invasive or already metastasized at time of diagnosis
Histologically bland and rarely exhibit marked anaplasia
More than 50% of the patients have diarrhea
Zollinger-Ellison syndrome is a rare condition in which one or more
gastrinomas form in the pancreas or the duodenum.

9. Rare Pancreatic Endocrine Neoplasms
α-Cell tumors (glucagonomas)
Associated with increased serum glucagon and a syndrome consisting of
mild diabetes mellitus, a characteristic skin rash and anemia
Occur most frequently in peri- and postmenopausal women and are
characterized by extremely high plasma glucagon levels

10. Rare Pancreatic Endocrine Neoplasms
δ-Cell tumors (somatostatinomas)
Associated with diabetes mellitus, cholelithiasis, steatorrhea, and
hypochlorhydria
High plasma somatostatin levels are required for diagnosis
VIPoma
An endocrine tumor which releases vasoactive intestinal peptide (VIP)
manifests as; watery diarrhea, hypokalemia, achlorhydria

11. References
Robbins Basic Pathology 10th edition by Kumar Abbas Aster
www.webpathology.com