Endocrine Abstracts

Introduction: Acromegaly is a systematic disease with charecteristic clinical features, which is due to GH hypersecretion mainly from pituitary adenomas and in rare cases it can be due to ectopic GHRH and GH hypersecretion. Sometimes localizing the source of hypersecretion is difficult. Here we present a case of a woman with acromegalic phenotype and empty sella.

Presentation: A 47 years old woman referred to our department after recent onset of high blood pressure, headache and dizziness and a head MRI which revealed an empty sella. Clinically she had acromegalic features and acromegaly was confirmed biochemically (IGF-1 941.1 ng/ml and basic GH 5.41 μg/l and after OGTT 3.36 μg/l). A pituitary MRI confirmed the empty sella with no obvious pituitary tissue present. In order to localize the source of the GH hypersecretion further biochemical and imaging tests were performed (plasma chromogranin and calcitonin, 24 hour urine metanephrines and nonmetanephrines, head and neck CT, abdomen CT, ¹¹¹ In-Octreotide scanning) and all were negative. Determination of IR-GHRH though was indicative of pituitary hypersecretion. Octreotide LAR 40 mg failed to result in biochemical control of the disease and Pegvisomant (10 mg/day) was added. Eleven months later biochemical control was achieved (normal for her age IGF-1 and GH < 1 μg/l), but a pituitary MRI at that time revealed an 9×4.4×6 mm adenoma.

Conclusions: Pegvisomant, a GH antagonist, used as monotherapy or in combination for treating acromegaly is very effective in controling the disease, but growth of the pituitary adenomas is being described in rare cases. Although when combined with somatostatin analog this risk is lower, in our case revealed the adenoma.