Pancreatic neuroendocrine tumors

What are PNETs and what cells do they derive from?

PNETs are hormone-secreting tumors of the pancreas that derive from neuroendocrine cells. Summary 1

What are the most important types of PNETs, excluding insulinomas and gastrinomas?

The most important types of PNETs, excluding insulinomas and gastrinomas, are glucagonomas, VIPomas, and somatostatinomas. Summary 2

What are the typical symptoms of PNETs (excluding insulinomas)?

PNETs typically manifest with diarrhea, weight loss, and normal or elevated blood glucose levels. Summary 3

How do insulinomas differ in presentation from other PNETs regarding bowel movements and blood glucose?

Insulinomas do not affect bowel movements and manifest with weight gain and hypoglycemia. Summary 4

What are the main diagnostic steps for PNETs?

Diagnosis involves laboratory studies to identify excess hormone levels and imaging to detect the primary tumor and metastases. Summary 5

What is the first-line treatment for PNETs?

Surgical resection is the first-line treatment for PNETs. Summary 6

What is the treatment of choice for inoperable PNETs?

Octreotide is the treatment of choice for inoperable PNETs. Summary 7

What cells are affected in Glucagonomas?

Glucagonomas affect α-cells. Overview 8

What is the typical blood glucose level in a Glucagonoma?

Blood glucose is elevated in a Glucagonoma. Overview 9

What gastrointestinal symptom is associated with Glucagonoma?

Glucagonomas sometimes cause watery diarrhea. Overview 10

What other clinical features are associated with Glucagonoma?

Glucagonomas can cause weight loss, necrolytic migratory erythema, neuropsychiatric symptoms, and thrombosis. Overview 11

What associated conditions are seen with Glucagonomas?

Glucagonomas are sometimes associated with MEN 1. Overview 12

What cells are affected in Insulinomas?

Insulinomas affect β-cells. Overview 13

What is the typical blood glucose level in Insulinomas?

Blood glucose is decreased in Insulinomas. Overview 14

Is diarrhea typically seen in Insulinomas?

No, diarrhea is not typically seen in Insulinomas. Overview 15

What other clinical feature is associated with Insulinomas?

Insulinomas cause weight gain and the Whipple triad. Overview 16

What cells are affected in Gastrinomas?

Gastrinomas affect non-β-cells. Overview 17

What is the typical blood glucose level in Gastrinomas?

Blood glucose is typically normal in Gastrinomas. Overview 18

What gastrointestinal symptom is seen with Gastrinomas?

Gastrinomas usually cause steatorrhea. Overview 19

What other clinical features are associated with Gastrinomas?

Gastrinomas cause weight loss, GERD, peptic ulcers, and signs of malabsorption. Overview 20

What cells are affected in VIPomas?

VIPomas affect nerve fibers innervating islets. Overview 21

What is the typical blood glucose level in VIPomas?

Blood glucose is elevated in VIPomas. Overview 22

What gastrointestinal symptom is associated with VIPomas?

VIPomas cause watery diarrhea. Overview 23

What other clinical features are associated with VIPomas?

VIPomas cause weight loss, hypokalemia, dehydration, and achlorhydria (anemia). Overview 24

What cells are affected in Somatostatinomas?

Somatostatinomas affect δ-cells. Overview 25

What is the typical blood glucose level in Somatostatinomas?

Blood glucose is elevated in Somatostatinomas. Overview 26

What gastrointestinal symptom is associated with Somatostatinomas?

Somatostatinomas cause steatorrhea. Overview 27

What other clinical features are associated with Somatostatinomas?

Somatostatinomas cause weight loss, glucose intolerance, and cholelithiasis. Overview 28

What conditions are associated with Somatostatinomas?

Somatostatinomas are associated with NF-1 and rarely MEN 1. Overview 29

What is the definition of a glucagonoma?

A rare neuroendocrine tumor of pancreatic α-cells that secretes glucagon. Glucagonoma 30

What is the prevalence of metastasis at diagnosis for glucagonomas?

Metastasis is present at diagnosis in > 50% of cases for glucagonomas. Glucagonoma 31

What clinical features are associated with glucagonomas?

Weight loss, impaired glucose tolerance or diabetes mellitus, necrolytic migratory erythema, chronic diarrhea, deep vein thrombosis, and depression. Glucagonoma 32

What is necrolytic migratory erythema?

A cutaneous paraneoplastic syndrome associated with glucagon-secreting pancreatic tumors, hepatitis B, C, and bronchial carcinoma. Glucagonoma 33

What are the characteristics of necrolytic migratory erythema?

Occurrence of multiple areas of centrifugally spreading erythema, located predominantly on the face, perineum, and lower extremities, developing into painful and pruritic crusty patches with central areas of bronze-colored induration, tending to resolve and reappear in a different location. Glucagonoma 34

What laboratory findings are seen in glucagonomas?

Increased glucagon (> 500 pg/mL), increased blood glucose levels, and normocytic normochromic anemia. Glucagonoma 35

What imaging is used to locate a glucagonoma tumor?

CT is used to locate the tumor. Glucagonoma 36

What are the treatment options for glucagonomas?

Glycemic control, tumor resection, and octreotide (if tumor is inoperable). Glucagonoma 37

What is the mnemonic for glucagonoma symptoms?

"Wait for 6 Days until the GLUe is dry" (Decreasing weight, Diabetes, Dermatitis, Diarrhea, DVT, Depression). Glucagonoma 38

What is the definition of a somatostatinoma?

A rare neuroendocrine tumor of δ-cell (D-cell) origin that is usually located in the pancreas or gastrointestinal tract and secretes somatostatin. Somatostatinoma 39

What effect does somatostatin have on other hormone secretions?

Somatostatin decreases secretion of secretin, cholecystokinin, glucagon, insulin, gastrin, and gastric inhibitory peptide. Somatostatinoma 40

What clinical features are associated with somatostatinomas?

Abdominal pain, weight loss, glucose intolerance/diabetes, cholelithiasis, steatorrhea, and achlorhydria. Somatostatinoma 41

What laboratory findings are seen in somatostatinomas?

Increased somatostatin and increased blood glucose levels. Somatostatinoma 42

What imaging is used to locate a somatostatinoma tumor?

Imaging (e.g., CT scan) is used to locate the tumor. Somatostatinoma 43

What are the treatment options for somatostatinomas?

Tumor resection, octreotide (if tumor is inoperable), and chemotherapy. Somatostatinoma 44

What is the definition of a VIPoma?

A neuroendocrine tumor that secretes VIP (vasoactive intestinal polypeptide). VIPoma 45

What syndrome is associated with VIPomas?

The WDHA syndrome (watery diarrhea, hypokalemia, achlorhydria) is associated with VIPomas. VIPoma 46

What is the etiology of VIPomas?

VIPomas are associated with MEN1 syndrome in 5% of cases. VIPoma 47

What is the pathophysiology of VIPomas?

Excess VIP causes increased relaxation of gastric and intestinal smooth muscles and cAMP activity, leading to secretory diarrhea and inhibition of gastric acid production, as well as stimulating vasodilation, bone resorption, and glycogenolysis. VIPoma 48

Where is the primary tumor most frequently found in VIPomas?

The primary tumor is most frequently found in the pancreas. VIPoma 49

What are the clinical features of VIPomas?

WDHA syndrome, watery diarrhea (> 700 mL/day), weight loss, abdominal pain, nausea, vomiting, achlorhydria, anemia. VIPoma 50

What diagnostic findings are seen in VIPomas?

Increased serum VIP concentration (> 75 pg/mL), hypokalemia, hypercalcemia, hyperglycemia, gastric achlorhydria or hypochlorhydria. VIPoma 51

What imaging is used to locate a VIPoma tumor?

CT scan to localize the primary tumor. VIPoma 52

What are the treatment options for VIPomas?

Tumor resection and octreotide (inhibits VIP secretion). VIPoma 53