Pheochromocytomas and paragangliomas are rare, with an estimated annual incidence of 2-8 per million population [1]. Hypertension, paroxysmal or sustained, is the most consistent finding [2]. The classical triad of symptoms, headache, palpitations and excessive sweating, is present in up to 50-70% of patients [2]. Other relatively common symptoms are flushing, pallor, anxiety, diarrhea, fatigue and fever. Here, we report a 9-year-old boy with bilateral pheochromocytoma, whose only presenting complaints were polyuria and polydipsia for two years.

Plasma and urinary normetanephrines were markedly elevated (2187 pg/mL (normal <180), and 3810 µg/day (normal 0-600) respectively), while the metanephrines were within normal levels, suggesting that the predominant catecholamine secreted by the tumor was norepinephrine. PET/CT showed tumor located in bilateral adrenals with no extra adrenal tissue involvement. MRI of the brain was normal.

The child was taken up for surgery after medical preparation. The left adrenal was completely removed, while a part of the right adrenal gland was left and secured in place. Antihypertensives were discontinued immediately after surgery and replacement doses of hydrocortisone and fludrocortisone were started. Inotropic support was needed for one day in postoperative period. Polyuria and polydipsia subsided completely within 3-4 days of surgery.

The child has been in regular follow up for the last 8 months. There is no polyuria, polydipsia or hypertension. Hydrocortisone and fludrocortisone were tapered successfully after six months of surgery, and serum cortisol documented to be within normal limits. Repeat MIBG and PET/CT done after 6 months of surgery to look for tumor recurrence were normal.

Presentation of pheochromocytoma with DI like symptoms is extremely uncommon. Only three earlier case reports have reported polyuria and polydipsia as major presenting complaints, and in two of these, there were other complaints that provided additional clues towards diagnosis [3-5]. Our case presented with polyuria and polydipsia as the predominant complaint, leading to delay in diagnosis despite consulting several physicians over a two year period. The hypertension in our case was not striking, and emphasized the fact that hypertension can be mild and paroxysmal in patients with pheochromocytoma.

Moreover, in experimental and clinical studies, administration of norepinephrine has been seen to cause a reduction in insulin secretion [9], as well as sensitivity [10]. The combined effect is therefore hyperglycemia, which can lead to solute mediated diuresis. In this child however, blood sugar was only mildly elevated, and therefore unlikely to be contributing to polyuria.

To conclude, we would like to state that polyuria and polydipsia can be the only presenting complaints in a child with pheochromocytoma, and BP measurement should be an integral part of initial evaluation of all children.

Contributors: VJ: drafted the paper, critically revised the manuscript for intellectual content, and will act as guarantor; JY: drafted the paper and reviewed the literature; AKS: was involved in drafting the paper and clinically managing the patient. The final manuscript was approved by all authors.

Funding: None; Competing interests: None stated.

1. Barontini M, Levin G, Sanso G. Characteristics of pheochromocytoma in a 4- to 20-year-old population. Ann NY Acad Sci. 2006;1073:30–7.

2. Ram CV, Fierro-Carrion GA.　Pheochromocytoma.　Semin Nephrol. 1995;15:126-37.

3. Tevetoglu F, Lee CH. Adrenal pheochromocytoma simulating diabetes insipidus: report of a case and review of the other pediatric cases. AMA J Dis Child. 1956;91:365-79

4. Stella P, Bignotti G, Zerbi S, Ciurlino D, Landoni C, Fazio F, et al.　Concurrent pheochromocytoma, diabetes insipidus and cerebral venous thrombosis-a possible unique pathophysiological mechanism. Nephrol Dial Transplant.　2000;15:717-71.

5. Baykan A, Narin N, Kendirci M, Akcakus M, Küçükaydýn M, Patýroðlu T. Pheochromocytoma presenting with polydipsia and polyuria in a child. Erciyes Týp Dergisi. 2005;27:128-31.

6. Schrier　RW,　Goldberg　JP. The physiology of vasopressin release and the pathogenesis of impaired water excretion in adrenal, thyroid, and edematous disorders. Yale J Biol Med. 1980;53:525-41.

7. Schrier RW, Berl T, Harbottle JA, McDonald KM. Catecholamines and renal water excretion. Nephron. 1975;15:186-96.

8. Schrier RW, Berl T. Mechanism of effect of alpha adrenergic stimulation with norepinephrine on renal water excretion. J Clin Invest. 1973;52:502-11.

9. Sorenson RL, Elde RP, Seybold V. Effect of norepinephrine on insulin, glucagon, and somatostatin secretion in isolated perifused rat islets. Diabetes. 1979;28:899-904.