[Acromegaly as a differential diagnosis of hyperphosphatemia]

Acromegaly is characterized by hypersecretion of growth hormone (GH) caused by a pituitary adenoma in 99% of cases. Increased serum phosphate is a rare finding in this pathology. This hyperphosphatemia results from increased phosphate reabsorption in the proximal renal tubule via sodium-phosphate cotransporter type IIa: an effect mediated by insulin-like factor 1 (IGF-1) consequent to excess GH. We present the clinical case of a 66-year-old woman with persistent hyperphosphatemia 4.8 ng/dl (VN: 2.5-4.5) with elevated tubular phosphorus reabsorption (TPR) 95% (VN: 85-94) with subtle features of acromegaly. Acromegaly was diagnosed by IGF1 measurements and oral glucose tolerance test with GH measurement (OGTT/GH). In search of the source of GH hypersecretion, a pituitary MRI was requested, and the pituitary microadenoma was evident only in the third year of follow-up. Achieving remission of the disease (IGF-1 in normal range) after transsphenoidal endoscopic surgery and observing normalization of previous hyperphosphatemia. No evidence of recurrence was found in the 18 years of follow-up. In cases of hyperphosphatemia to review the signs and symptoms of acromegaly to diagnose and treat in early stages, when the probability of remission is high.