Endocrine Abstracts

Acromegaly is caused by growth hormone-secreting adenoma in more then 95% cases. Ectopic secretion of GH-RH is a rare cause of acromegaly accounting for less than 1% of all cases. The most frequent source of ectopic GHRH is bronchial carcinoid. Clinical and biochemical findings are similar in both conditions. A distinction of pituitary vs extrapituitary acromegaly is important in planning effective management and both reasons should be considered in the diagnostic process.

Case report: An 80-year-old woman with the clinical features of acromegaly (hypertension, congestive heart failure, osteoarthritis of the knees, carpal tunnel syndrome, enlargement of mandibule, hands and feet) was admitted to the Endocrinology Unit for further evaluation. The lab test confirmed acromegaly. The pituitary tumor was not found on MRI. The hypothesis of acromegaly secondary to ectopic GHRH secretion was propounded. The lung tumors (9×9×6 mm and 5 mm) were detected in CT scans. There was no confirmation of lung or pituitary pathology in somatostatin receptor scintigraphy. PET-CT revealed a presence of higher expression of somatostatin receptors in 10th segment of left lung. The lung tumor was successfully removed (histologically NET). The postoperative IGF1 level was still elevated with no GH suppression during the OGTT. The MRI of the pituitary was repeated and finally pituitary tumor was found (3.5×7×4.5 mm anterior lobe). The patient was successfully operated and biochemically cured.

Conclusions: Despite the rare occurrence of acromegaly, it shoild always be considered during the diagnosis. Only detailed evaluation may facilitate prompt diagnosis and recovery from this destructive disease.