Endocrine Abstracts (2012) 29 P349

A case of acromegaly without clear evidence of pituitary adenoma or ectopic GH/GHRH secreting tumors

B. Fibbi, C. Maggioli, L. Vannucci, M. De Feo, L. Petrone, A. Cilotti, G. Forti & C. Pupilli

Careggi Hospital and University of Florence, Florence, Italy.

Introduction: Acromegaly secondary to an extrapituitary source of GH or GHRH is rare, usually associated with bronchial/thymic carcinoids, neuroendocrine enteropancreatic tumors or extrasellar somatotropinomas. Few series of acromegalic patients with negative pituitary imaging and lack of an ectopic source are reported in the literature.

Methods: We report the clinical history and the laboratory and imaging results of an acromegalic woman with no clear evidence of pituitary somatotropinoma or ectopic GH/GHRH source.

Results: A 66-year-old woman was referred to our outpatient clinic for the follow-up of a multifocal differentiated thyroid carcinoma treated by total thyroidectomy 7 years before. The thyroid oncologic follow-up was negative but physical examination revealed acromegalic features. She also complained frontal headache, amaurosis, fatigue, paraesthesias, muscular pains and sleep apnea syndrome. Basal IGF1 levels resulted elevated for age (312 ng/ml; r.v. 78-212), and a nadir GH of 1.45 ng/ml during oral glucose tolerance test (OGTT) was diagnostic for acromegaly. Magnetic resonance imaging of the pituitary was unremarkable but an abnormal contrast-enhancement of the right cavernous sinus (CS) was present. Computed tomography of chest and abdomen and a whole body Octreoscan didn’t show any evidence of ectopic GH/GHRH-releasing tumor. Short-acting octreotide formulation treatment was started as once-daily administration because of gastrointestinal intolerance, with a partial biochemical remission of acromegaly. Nine months later, octreotide was discontinued and OGTT and imaging scans were repeated, confirming previous observations.

Conclusions: The described patient did not show an obvious source of GH or GHRH secretion. So far, only one case of ectopic somatotropinoma has been described in the CS. A trans-sphenoidal exploration could be crucial in our patient in order to exclude a micro-adenoma of the pituitary and explore the possibility of an CS ectopic somatotropinoma, thus avoiding further invasive and expensive imaging tests.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.

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