All pheochromocytomas are biochemically undetectable when small—they require a sizable “factory” to become biochemically detectable. Thus publications that report that a laboratory test is 98% or 100% sensitive in detecting pheochromocytomas is simply wrong—just not possible! Computed abdominal imaging is being performed for a never-ending list of reasons. We are finding “baby” pheochromocytomas before they become symptomatic or biochemically detectable. Herein is such a case.
The patient was a healthy 49-year-old man who had been troubled by intermittent right upper quadrant pain, which was thought to be related to gallbladder dysfunction. Abdominal computed tomography (CT) incidentally discovered a 1.6-cm lipid-poor and vascular left adrenal mass ( Fig. 36.1 ). He had no signs or symptoms of adrenal cortical or medullary dysfunction. He took no regular medications. His blood pressure was 128/78 mmHg, heart rate 74 beats per minute, and body mass index 26.51 kg/m 2 .
All adrenal-related laboratory studies normal ( Table 36.1 ).
|Biochemical Test||Result||Reference Range|
am serum cortisol, mcg/dL
Plasma metanephrine, nmol/L
Plasma normetanephrine, nmol/L
Plasma renin activity ng/mL per hour