A 31-year-old man presents to the emergency room complaining of weakness, palpitations, diaphoresis, and irritability. He has had several similar episodes in the past few weeks, none as severe as this one. Physical exam is unremarkable. The nurse performs a fingerstick to check his blood glucose, which is found to be 39. Administration of glucose relieves his symptoms. Serum calcium is 11.1. A mass in which of the following structures is likely responsible for his presenting symptoms?
A. Liver
B. Pancreas
C. Prostate
D. Small intestine
E. Stomach
A. Liver
B. Pancreas
C. Prostate
D. Small intestine
E. Stomach