Exp Clin Endocrinol Diabetes 2005; 113 - 158
DOI: 10.1055/s-2005-863017

Acromegaly caused by a thoracic neuroendocrine tumor

C Trantakis 1, C Koch 2, A Tannapfel 3, J Meixensberger 1, K Drynda 4, D Führer 2
  • 1Klinik für Neurochirurgie, Leipzig
  • 2Medizinische Klinik III, Leipzig
  • 3Institut für Pathologie, Leipzig
  • 4Praxis für Endokrinologie, Leipzig

A 40 yr. old female watchmaker presented for evaluation of longstanding multinodular goitre and was noted to have acromegalic features. She reported a >10 yr. history of progressive increase in ring and shoe size, profuse sweating, oligomenorrhea and hirsutism. In addition, she had mild arterial hypertension. Levels of IGF-1 were 648 (SDS + 3.41, age- and sex-matched) and of growth hormone were >25µg/l during an oral glucose suppression test. MRI showed a profusely enlarged pituitary gland without an adenoma, raising the suspicion of ectopic GHRH production. An octreotide scan showed impressive focal left-thoracic uptake, corresponding to a 7×5cm thoracic tumour on a CT-scan. Subsequently, the patient underwent tumour resection. Histopathology showed a bronchial neuroendocrine tumor. There were no lymph node metastases. Postoperatively, the woman reported marked improvement of soft tissue swelling and sweating as well as decrease of goitre size. Menstrual cycles normalized and hirsutism improved. Antihypertensive treatment was omitted. Follow-up octreotide scans were negative. At 3 months f/u, the pituitary gland had normal size on MRI. In addition, thoracic CT- scan and bronchoscopy were normal. Although results of the oral glucose (75g) tests at 6 weeks and 3 months postoperatively were equivocal (0.99–1.1µg/l), IGF-1 levels dropped to 219 (SDS: +0.9) and have remained within normal range since.

Acromegaly caused by ectopic GHRH production accounts for <1% of cases of acromegaly. Approx. 30% of these cases are thoracic neuroendocrine tumors. In the absence of a pituitary lesion on MRI, further imaging is mandatory in all patients with GH excess. In this scenario, octreotide scanning may be particularly useful to detect a GHRH producing tumor.