What does the GH-producing pituitary adenoma look like at diagnosis on 3.0T MRI and what does it tell us?

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 88-129-Acromegaly & Prolactinoma
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-126
Iulia Potorac1, Patrick Petrossians2, Franck Schillo3, Gerald Raverot4, François Cotton4, Anne Boulin5, Stephan Gaillard5, Luaba Tshibanda1, Albert Beckers2 and Jean Francois Bonneville*1
1CHU, University of Liège, Liège, Belgium, 2CHU de Liège-University of Liège, Liège, Belgium, 3CHU Jean Minjoz, Besançon, France, 4Hospices Civils de Lyon, Lyon Cedex 03, France, 5Hopital Foch, Suresnes, France
Introduction: Although a number of publications refer to the evolution of growth hormone (GH)-producing pituitary adenomas after medical therapy associated or not to surgery, no study on an important number of acromegalic patients establishes the typical radiologic features of this type of adenoma. The aim of this study was to characterize the aspect of the pituitary GH-producing adenoma on 3.0T magnetic resonance imaging (MRI) at diagnosis, therefore prior to any treatment and to correlate T2-signal with the local development of the adenoma and the biochemical features.

Materials and methods: 110 acromegalic patients were included in this retrospective multicentric study. An evaluation of their diagnostic 3.0T MRI was performed in order to determine the following characteristics of the adenoma: T2-weighted signal (defined by comparison with the normal pituitary tissue and only when the latter was not visualised, with the cerebral grey matter), vertical extrasellar extension, lateral invasion of the cavernous sinus, maximum diameter. IGF1 value at diagnosis was also retained as a ratio from the superior normal laboratory limit for age and sex.

Results: Of the 110 pituitary GH-secreting adenomas reviewed, 67,3% were T2 hypointense and 32,7% hyperintense. The age at diagnosis was significantly lower in men compared to women (P=0,01). More than half of the GH-secreting adenomas manifest a proclivity for infrasellar extension, independent of T2-signal. Hypointense T2 adenomas compared to the hyperintense ones invade less the cavernous sinus (P=0,04), are associated with higher IGF1 levels (P=0,01) and tend to be smaller (P=0,07).

Conclusions: Our study establishes the first 3.0T MRI description of the typical features of GH-producing adenomas at the diagnosis of acromegaly on an important number of patients. These adenomas are more frequently hypointense on T2-weighted MRI and, irrespective of their signal, are associated with a younger age at diagnosis in men than in women and present a tendency towards infrasellar extension. T2-hypointense adenomas generally do not invade the cavernous sinus, are associated with a higher production of GH as proven by the higher IGF1 levels and are smaller than their hyperintense counterparts. These observations support the importance of T2-signal description of GH-producing pituitary adenomas and incite towards further studies that could evaluate the prognostic value of the radiologic characterization.

Nothing to Disclose: IP, PP, FS, GR, FC, AB, SG, LT, AB, JFB

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm