Neuroendocrine Tumors of Pancreas

The WHO 2019 Classification, Terminology of NEC vs NET

• NEC is clearly indicative of high-grade malignant histology and biologic behavior.
• Neuroendocrine tumor (NET), in contrast, is intended to designate a family of well-differentiated neoplasms whose potential to metastasize or invade the adjacent tissues depends on the tumor site and grade.
• All neuroendocrine neoplasms have malignant potential.

Mutations in NET vs NEC & PNET vs PDAC :

AJCC vs ENETS Staging of PNET’s:

Functional Pancreatic Neuroendocrine Tumors:

INSULINOMA

• Benign,(90%) can be malignant(10%)
• Do not express SST receptor = therefore we cannot use SR scintigraphy in diagnosis ⇒ therefore we use EUS / CECT
• Uniformly across pancreas
• MEN 1/sporadic cases
• Fasting hypoglycemia, seizures, personality disorder, weight gain

Diagnosis:

• 72 hour fast test
  • Critical sample : Increased C peptide level, glucose, insulin
    • Glucose < 45 mg/dL,serum insulin >5 uU/L, C peptide >0.7 ng/ml
• Imaging : Pancreatic protocol CT is IOC
• EUS; intraoperative ultrasound
• Exendin scan: GLP-1 analogue

Glucagonoma

• Large solitary
• F>M
• MC location: body and tail
• Malignant in 50-80% of time
• Glucose intolerance, migratory necrolytic erythema, weight loss = typical triad [ as glucagon is a catabolic hormone]
  • Diabetes is Mild in nature
• Rash: perineum and spreads to trunk and extremities
• Diabetes, dermatitis, DVT, depression
• Weight loss, vitamin deficiencies
• DIAGNOSIS:
  • Fasting glucagon >100 pg/ml
• Preoperative treatment of Glucagonoma:
  • DVT prophylaxis
  • IV amino acids lead to disappearance of rash
  • Diabetes is mild = so no need for insulin
• 60% will have liver metastases
• 5 year survival
  • is nearly 85% (absence of metastasis)
  • With mets (60%)

Gastrinoma

• MC clinical presentation: Pain in abdomen
• Cause of diarrhea: Acid production
• MC location: First part of duodenum
• Lab:
  • Gastrin > 1000 pg/ml
  • Gastric pH < 2
  • Secretin stimulation test: Gastrin level more than 200 pg/ml
  • Hypergastrinemia with high acid production

• Localisation:
  • CECT: hyperenhancing lesion
  • SRS scan: Most sensitive and specific
  • EUS
• Presence of malignant disease is the most important prognostic factor (not lymph nodes)
• Pancreas location predicts more aggressive disease
• Exploration if no preoperative localisation
• Aggressive surgical therapy