Is an Islet Cell Tumor a Neuroendocrine Tumor?

Pancreatic neuroendocrine tumors can be benign (noncancerous) or malignant (cancerous). 

The pancreas is a flat pear-shaped organ, about six inches long, located behind the stomach and in front of the spine. It is divided into three parts—the wider end is called the head, the middle section is called the body, and the narrow end is called the tail. 

The pancreas comprises two types of cells that include:

1. Endocrine cells or islets of Langerhans: Responsible for producing hormones such as insulin to control blood sugar
2. Exocrine cells: Responsible for producing enzymes that are released into the small intestine to help the body digest food

1. Functional tumors: Produces excess hormones, such as gastrin, insulin, and glucagon, which cause signs and symptoms. Most pancreatic neuroendocrine tumors are functional tumors.
   • Gastrinoma: A tumor that forms in the cells that produce gastrin, a hormone responsible for making the stomach release acid to help digestion.
   • Insulinoma: A tumor that forms in the cells that produce insulin, a hormone responsible for controlling the amount of glucose in the blood.
   • Glucagonoma: A tumor that forms in the cells that make glucagon, a hormone responsible for increasing the amount of glucose in the blood.
   • Others: Rare types of tumors of the cells that produce hormones responsible for controlling the balance of sugar, salt, and water in the body.
     • VIPomas (produce vasoactive intestinal peptide)
     • Somatostatinomas (produce somatostatin)
2. Nonfunctional tumors: Signs and symptoms are often caused by the growth and spread of the tumor. Most nonfunctional tumors are malignant.

Four stages of pancreatic neuroendocrine tumors include:

1. Stage I: A small tumor restricted to the pancreas (T1, N0, M0)
2. Stage II: The tumor is large but has not spread to the regional lymph nodes (T2 or T3, N0, M0)
3. Stage III: The tumor is of any size and has spread to the regional lymph nodes or the stomach, spleen, colon, and adrenal gland (T4, N0, M0)
4. Stage IV: The tumor has metastasized to distant parts of the body (any T, any N, M1)

The signs or symptoms are either caused by the growth of the tumor and/or by the hormones produced by the tumor.

Nonfunctional pancreatic neuroendocrine tumor (NET)

• Diarrhea
• Indigestion
• A lump in the abdomen
• Abdominal or back pain
• Yellowing of the skin
• Inflamed mouth and tongue
• Clouding of vision

Functional pancreatic NET

Depending on the type of hormone being produced, signs and symptoms of a functional pancreatic NET include:

• Gastrin
  • Recurring stomach ulcers 
  • Pain in the abdomen (on and off and relieved by taking an antacid)
  • Gastroesophageal reflux
  • Diarrhea
• Insulin
  • Hypoglycemia (low blood sugar levels)
    • Blurred vision
    • Headache
    • Light-headedness
    • Tiredness 
    • Weakness
    • Nervous
    • Irritable
    • Sweaty
    • Confused
  • Tachycardia (fast heartbeat)
• Glucagon
  • Rash on the face/stomach/legs
  • Hyperglycemia (high blood sugar levels)
    • Headache
    • Frequent urination
    • Dry skin and mouth
    • Feeling hungry, thirsty, tired, or weak
  • Blood clots
  • Diarrhea
  • Unintentional weight loss
  • Sore tongue 
  • Sores at the corners of the mouth
• Vasoactive intestinal peptide
  • Watery diarrhea
  • Dehydration
    • Feeling thirsty
    • Decreased urination 
    • Dry skin and mouth
    • Headaches
    • Dizziness
    • Feeling tired
  • Hypokalemia (low blood potassium levels) 
    • Muscle weakness
    • Aching or cramps
    • Numbness and tingling
    • Frequent urination
    • Fast heartbeat
    • Feeling confused or thirsty
  • Cramps or pain in the abdomen
  • Unintentional weight loss
• Somatostatin
  • Hyperglycemia
  • Diarrhea
  • Steatorrhea (foul-smelling stool that floats)
  • Gallstones
  • Yellowing of the skin
  • Unintentional weight loss 
• Adrenocorticotropic hormone
  • Headache
  • Loss of vision
  • Weight gain particularly on the face, neck, and trunk 
  • Buffalo hump
  • Purple/pinkish stretch marks on the chest or abdomen
  • Easy bruising
  • Fine hairs on the face, upper back, or arms
  • Bones that break easily
  • Sores or cuts that heal slowly
  • Anxiety, irritability, and depression

To diagnose pancreatic neuroendocrine tumors (NETs), the following tests and procedures may be used:

• Physical examination: To check for general signs of the disease.
• Blood tests: To measure the amounts of glucose, potassium, and several hormone levels.
• Chromogranin A test: To measure the level of chromogranin A in the blood.
• Abdominal CT scan: To take a series of detailed pictures of the abdomen from different angles.
• MRI scan: To take a series of detailed pictures of areas inside the body using magnets, radio waves, and a computer.
• Somatostatin receptor scintigraphy: A radionuclide scan to find small pancreatic NETs.
• Endoscopic retrograde cholangiopancreatography: Tissue samples are taken using an endoscope and checked under a microscope for signs of cancer.
• Biopsy: Cells or tissues are removed to be viewed under a microscope.

The prognosis depends on the following:

• Type of cells
• Whether the tumor is restricted or localized to the pancreas
• Metastasis (spread to other parts of the body)
• Age
• Overall health 
• Whether the cancer is currently being treated or has relapsed

The types of treatment for pancreatic neuroendocrine tumors include:

• Surgery
  • Enucleation: Removal of the entire tumor
  • Pancreatoduodenectomy: Removal of the head of the pancreas, gallbladder, nearby lymph nodes, and part of the stomach, small intestine, and bile duct
  • Total gastrectomy: Removal of the stomach
  • Parietal cell vagotomy: Surgical excision of the nerve responsible for acid stimulation
  • Liver resection: Removal of a part or entire liver
  • Radiofrequency ablation: Cancer cells are killed using a special probe with tiny electrodes
  • Cryosurgical ablation: Abnormal cells are destroyed by the tissue freezing technique
• Chemotherapy
• Hormone therapy
• Hepatic arterial occlusion or chemoembolization
• Targeted therapy
• Supportive care