A 40-year-old woman with hypertension comes to the physician because of excessive thirst, excessive urination, constipation, and a depressed mood. Her medications include hydrochlorothiazide. Laboratory studies show a serum calcium level of 11.0 mg/dL. 
Which of the following underlying disorders is most likely?
Medullary carcinoma of the thyroid
Multiple myeloma
Parathyroid adenoma
Porphyria