A 42-year-old man presents to the emergency department complaining of heart palpitations and severe ‘crushing’ headaches. He tells you that he has had similar episodes of these symptoms in the past. He describes his palpitations as “spells during which I am going to die.” As you talk to him, you notice severe flushing on his body and he is drenched in sweat. Physical examination revealed a blood pressure of 140/90 mm Hg and heart rate of 94/minute. During the physical examination, palpation of the abdomen elicited a sudden episode, during which the patient became profusely sweaty with facial pallor. You noticed a rise in blood pressure to 215/130 mm Hg and heart rate to 130 /minute. You immediately admit the patient to the hospital for acute treatment of his hypertension and to run additional tests.While administering appropriate treatment to lower his blood pressure, you begin to wonder if this patient might have an endocrinological disorder. You received the following laboratory results: urinary metanephrine 92 µg/dL (30–180) and normetanephrine 3943 µg/dL (111–419), plasma metanephrine 84 pg/mL (<100), and normetanephrine 3129 pg/mL (<167). Of the following, which is the likely diagnosis in this patient?
