Ectopic growth hormone-releasing hormone secretion by a bronchial carcinoid tumor: clinical experience following tumor resection and long-acting octreotide therapy

Riferimento: 
Pituitary. 2012 Jun;15(2):260-5.
Autori: 
Butler PW, Cochran CS, Merino MJ, Nguyen DM, Schrump DS, Gorden P.
Fonte: 
Pituitary. 2012 Jun;15(2):260-5.
Anno: 
2012
Azione: 
In un tumore carcinoide da acromegalia secondaria, dopo la resezione del tumore, fu testata una terapia con 10 mg di octreotide a lunga durata d'azione (Sandostatina®, LAR®).
Target: 
Octreotide LAR/tumore carcinoide da acromegalia secondaria.

ABSTRACT

Acromegaly resulting from the ectopic secretion of growth hormone-releasing hormone (GHRH) is rare. We present a case of acromegaly secondary to proven GHRH-secretion by a bronchial carcinoid tumor in a type 1 diabetic subject and document the clinical course pre- and post-resection of the tumor and of subsequent octreotide therapy. A 54-year-old Caucasian man was referred for evaluation of acromegalic symptoms and significantly increased insulin requirements. He had a history of left lung surgery 20 years prior for hemoptysis. Initial laboratory results indicated acromegaly. Fasting serum growth hormone (GH): 26.1 ng/mL (0-5 ng/mL), insulin-like growth factor 1 (IGF-1): 635 ng/mL (87-283 ng/mL), GH at 60 min post-ingestion of 75 grams of oral glucose during a glucose tolerance test: 8.3 ng/mL (normal <1 ng/mL). Pituitary magnetic resonance imaging (MRI) revealed diffuse pituitary enlargement without adenoma. A 4.4 cm left hilar mass was noted on chest computed tomography (CT) scan. Further evaluation for a suspected GHRH-secreting neuroendocrine tumor was pursued. Plasma GHRH level was elevated: 198 pg/mL (<50 pg/mL). Octreoscan showed radiolabelled-octreotide uptake in the left lung mass and pituitary gland. Surgical resection of the lung mass was performed. Immunohistochemical study of the tumor tissue indicated a neuroendocrine tumor secreting GHRH. Postoperatively, serum GHRH, GH and IGF-1 levels fell precipitously. At 10 months, IGF-1 levels were mildly elevated and 7 months of 10 mg long-acting octreotide therapy (Sandostatin(®) LAR(®)) was trialed. At 20 months, off octreotide, serum IGF-1 levels had normalized, acromegalic features were receding, and the patient's daily insulin requirements had decreased by 57%.
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