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?
Correct Answer: Alpha cell
Description: The symptoms described are typical for a patient with glucagon excess. Glucagon is secreted by alpha cells of the pancreatic islets of Langerhans. Increased levels are rare, usually due to carcinoma (70%) or adenoma (30%) of the islets. Two-thirds of patients with carcinoma have liver metastasis at the time of diagnosis. Increased glucagon causes a syndrome similar to diabetes mellitus, due to antagonism of insulin effects. Patients also have migratory skin rashes, alopecia, hyperpigmentation of the skin, and glossitis. Diagnosis is made by measuring glucagon. The acinar cell , the main exocrine cell of the pancreas, contains digestive enzymes. Increases in the release of these enzymes (especially amylase and lipase) occur with pancreatitis. Acute pancreatitis is considered an emergent medical condition. Chronic pancreatitis is associated with fibrosis and atrophy of the acinar structures. Beta cells are responsible for insulin release. An adenoma of beta cells (insulinoma) would cause hyperinsulinism. 70% are solitary and 10% are multiple. Insulinomas cause hypoglycemia, dizziness, confusion, and excessive sweating. Glucose needs to be given promptly to avoid coma and death. Diagnosis is made by finding increased insulin and hypoglycemia. Delta cells are islet cells that secrete somatostatin. Tumors producing increased somatostatin are usually malignant. Clinically, a diabetes mellitus-like syndrome occurs along with diarrhea. Diagnosis is made from elevated serum somatostatin levels, but can be difficult because of the hormone's sho half-life. Ref: German M.S. (2011). Chapter 17. Pancreatic Hormones and Diabetes Mellitus. In D.G. Gardner, D. Shoback (Eds), Greenspan's Basic & Clinical Endocrinology, 9e.
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