Endocrine Abstracts

Background: While the classic presentation of pheochromocytoma includes a triad of episodic headaches (90%), diaphoresis (60–70%), and palpitations (70%), literature has suggested 10% to 17% of patients with pheochromocytoma are either asymptomatic or mildly symptomatic; thus, highlighting the importance of appropriate endocrine work up of adrenal incidentalomas.

Case: We report a 37-year-old male with a long-standing history of nocturia and dysuria, who was managed by a urologist for prostatitis. Further evaluations with CT-kidneys, ureters and bladder showed an incidental rounded left 3×2 cm mildly hyper-attenuating adrenal mass, and the patient was referred to Endocrinology clinic for assessment of the adrenal incidentaloma. Other than dysuria and nocturia, no history of headache, diaphoresis, palpitations, or hypertension were of note. There was no family history for pheochromocytoma or paraganglioma. Physical examination was unremarkable including heart rate and blood pressure (24-hour blood pressure monitoring showing an overall average of 124/86 mmHg, with a range of 117/77 to 126/88 mmHg). Adrenal hormone work-up showed elevated plasma normetadrenalin [1.2 nmol/l (reference range <0.71)] and plasma metadrenalin [5.62 nmol/l (reference range<0.36)]. A repeat test showed a persistent elevation of both plasma normetadrenalin and metadrenalin at 1.52 nmol/l and 6.52 nmol/l, respectively. Other tests including full blood count, renal, liver and bone profiles, urinalysis, urine culture and sensitivity, FSH, LH, testosterone, post-dexamethasone suppression test cortisol (26 nmol/l), serum aldosterone (143 pg/ml), active renin (5.6 pg/ml), aldosterone:renin ratio (25.54), DHEAS (8.96 μmol/l) and delta androstenedione (4.89 nmol/l) were within normal limits. CT adrenals with contrast demonstrated a left adrenal rounded 3 cm mass with Hounsfield unit 43/84/60 and absolute washout calculation 60% and relative washout 28%, which is not consistent with adenoma. Echocardiogram showed no significant abnormality thus out-ruling catecholamine associated cardiomyopathy and an MIBG scan was also indicative of a solitary left sided pheochromocytoma. Following a course of alpha blockade with doxazocin, the patient underwent laparoscopic resection of the left adrenal mass and it was confirmed to be pheochromocytoma histologically. At post-surgery the patient remained well and repeat plasma metanephrine levels were within normal limits and required no long-term medications. Genetic tests results concluded no genetic abnormality was detected.

Conclusion: Our case demonstrated that a patient may not have classical symptoms of pheochromocytoma but could have significantly elevated plasma metanephrine levels. Our case also highlights the importance of an urgent assessment of adrenal masses in people <40 years of age as recommended by European Society of Endocrinology clinical practice guideline on adrenal incidentalomas.