Endocrine Tumors of Pancreas

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PNETs Overview - Pancreatic Powerhouses

  • Pancreatic Neuroendocrine Tumors (PNETs): Originate from pancreatic islet cells.
  • WHO 2019/2022 Classification & Grading:
    • Well-differentiated PNET (morphology preserved):
      • G1: Mitoses <2/10 HPF AND Ki-67 <3%
      • G2: Mitoses 2-20/10 HPF OR Ki-67 3-20%
      • G3: Mitoses >20/10 HPF OR Ki-67 >20%
    • Poorly-differentiated Neuroendocrine Carcinoma (NEC G3): High grade, poor morphology, Ki-67 often >55%.
    • MiNEN (Mixed Neuroendocrine-Non-neuroendocrine Neoplasm).
  • Functional (hormone-secreting, e.g., Insulinoma, Gastrinoma) vs. Non-functional (more common, present with mass effects).

⭐ Most PNETs are well-differentiated tumors (G1/G2), but Ki-67 index and mitotic count are crucial for grading and prognosis. Pancreatic Neuroendocrine Tumor Histopathology & Markers

Functional PNETs: Insulinoma & Gastrinoma - Sweet & Sour Syndromes

  • Insulinoma ("Sweet")

    • Most common PNET; β-cell origin; secretes insulin → hypoglycemia.
    • Whipple's Triad:
      • Hypoglycemic symptoms.
      • Plasma glucose <50 mg/dL.
      • Relief with glucose.
    • Dx: ↑Insulin, ↑C-peptide with hypoglycemia (72-hr fast).
    • ~90% benign, solitary. Tx: Surgery.
  • Gastrinoma ("Sour") - Zollinger-Ellison Syndrome (ZES)

    • G-cell origin (pancreas/duodenum); secretes gastrin → ↑HCl.
    • Clinical: Refractory/multiple peptic ulcers (PUDs), diarrhea.
    • Dx:
      • ↑Fasting gastrin (>1000 pg/mL with gastric pH <2).
      • Positive Secretin stimulation test (paradoxical ↑gastrin).
    • ~25% MEN1 associated. >60% malignant.
    • Tx: PPIs, surgery.

PNET Treatment Algorithm

⭐ Insulinomas are typically benign (~90%) and solitary, presenting with Whipple's triad, while gastrinomas (ZES) are often malignant, multiple, and associated with MEN1.

Other Functional PNETs - Rare Hormone Havoc

  • Glucagonoma:
    • Presents with syndrome: Diabetes, Dermatitis (necrolytic migratory erythema), DVT, Depression (📌 4Ds).
    • ↑ Glucagon. Often in pancreatic tail. High malignant potential.

    ⭐ Glucagonoma syndrome classically presents with the '4Ds': Dermatitis (necrolytic migratory erythema), Diabetes, DVT, and Depression.

  • VIPoma (Verner-Morrison Syndrome):
    • Causes WDHA syndrome: Watery Diarrhea, Hypokalemia, Achlorhydria ("Pancreatic Cholera").
    • ↑ VIP. Often in pancreatic tail. ~50% malignant.

    ⭐ VIPomas cause WDHA syndrome (Watery Diarrhea, Hypokalemia, Achlorhydria).

  • Somatostatinoma:
    • Syndrome: Diabetes mellitus, cholelithiasis, steatorrhea, hypochlorhydria.
    • ↑ Somatostatin. Often duodenal or pancreatic. Psammoma bodies common.
  • PPoma (Pancreatic Polypeptide-oma):
    • Often clinically silent or presents with vague symptoms. ↑ Pancreatic Polypeptide.

Necrolytic migratory erythema in Glucagonoma syndrome

PNETs: Diagnosis & Management - Spotting & Stopping

  • Diagnosis

    • Clinical Suspicion: Symptoms (hormonal/mass) or incidental finding.
    • Biochemical Markers:
      • Specific hormone assays.
      • General: Chromogranin A (CgA), Synaptophysin (IHC markers).
    • Imaging:
      • CT/MRI (initial).
      • EUS-FNA (biopsy).
      • Functional: Ga-68 DOTATATE PET/CT (best for staging/localization) or Octreoscan.

    ⭐ Chromogranin A and Synaptophysin are key immunohistochemical markers for PNETs. Somatostatin receptor scintigraphy (Octreoscan) or Ga-68 DOTATATE PET/CT are crucial for localization and staging.

  • Management

    • Surgery: Primary treatment for localized PNETs; curative intent.
    • Medical Management (for unresectable/metastatic disease):
      • SSAs (Octreotide, Lanreotide): Control symptoms, inhibit growth.
      • Targeted Therapy: Everolimus (mTORi), Sunitinib (TKI).
      • PRRT: Lu-177 DOTATATE for SSTR-positive tumors.
      • Chemotherapy (e.g., Streptozocin, Temozolomide): Poorly differentiated/high-grade.

Ga-68 DOTATATE PET CT of PNET

High‑Yield Points - ⚡ Biggest Takeaways

  • Insulinoma: Most common PNET, causes hypoglycemia (Whipple's triad); often benign.
  • Gastrinoma (ZES): Leads to multiple, refractory peptic ulcers; strong MEN 1 association.
  • Glucagonoma: Presents with necrolytic migratory erythema, diabetes, DVT, depression (4Ds).
  • VIPoma: Characterized by WDHA syndrome (Watery Diarrhea, Hypokalemia, Achlorhydria).
  • Somatostatinoma: Causes inhibitory effects: diabetes, cholelithiasis, steatorrhea, hypochlorhydria.
  • MEN 1 syndrome is frequently linked with gastrinomas, insulinomas, and glucagonomas.
  • Chromogranin A & Synaptophysin are key immunohistochemical markers for PNETs.

Practice Questions: Endocrine Tumors of Pancreas

Test your understanding with these related questions

A 38-year-old female presents to the physician with complaints of excessive thirst and urination for the past 4 weeks. Her appetite has been normal and she has not had diarrhea. Blood chemistry showed mildly elevated glucose and glucagon. Physical examination reveals tenderness in the left upper quadrant and an erythematous necrotizing skin eruption on her legs. Radiographic studies show a tumor in the pancreas. Which of the following cells is responsible for this lesion?

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Flashcards: Endocrine Tumors of Pancreas

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What hormone receptors are positive in mucinous cystadenomas of the pancreas?_____

TAP TO REVEAL ANSWER

What hormone receptors are positive in mucinous cystadenomas of the pancreas?_____

estrogen and progesterone

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