Silent Somatotroph Adenomas

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-121
Veronique Pelletier*1, France Berthelet2, André Lacroix3, Isabelle Bourdeau4, Catherine Beauregard5, Sophie Vallette6, Claire Girard7 and Omar Serri8
1Centre hospitalier de l'Université de Montréal, Montreal, QC, Canada, 2Centre Hospitalier de l'Université de Montréal, hôpital Notre-Dame, Montreal, QC, Canada, 3Centre Hospitalier de l'Université de Montréal, Montreal, QC, Canada, 4CHUM, Montreal, QC, Canada, 5Notre Dame Hospital, Montreal, QC, Canada, 6Hopital Notre-Dame du CHUM, Montreal, QC, Canada, 7Centre hospitalier de l'Université de Montréal, hôpital Notre-Dame, Montreal, QC, Canada, 8Notre-Dame Hospital, University of Montreal, Montreal, QC, Canada
Silent pituitary adenomas are so designated because they are not associated with clinical or biochemical evidence of hormone excess. Silent somatotroph adenomas are considered to be rare and can be either clinically silent or clinically and biochemically silent. The prevalence of each subtype is not well known. It has been recently reported that clinically silent somatotroph adenomas could represent as much as one third of all somatotroph tumors 1.

The goal of this study was to determine the prevalence of clinically silent and completely silent somatotroph adenomas in a large cohort of patients who underwent resection of a pituitary adenoma in our institution.

Design : Review of the pathology reports of patients who underwent resection of pituitary adenomas at a pituitary referral center between 2000 and 2012.

Methods : All pituitary lesions other than adenomas were excluded. We reviewed clinical and biochemical data of patients with adenomas identified by immunohistochemistry as somatotroph adenomas.

Results : A total of 412 patients underwent resection of a pituitary adenoma at Notre-Dame Hospital between January 1, 2000 and June 1, 2012. In 76 of these adenomas, the cell type was somatotroph. Seven patients had adenomas of the silent type, one microadenoma and six macroadenomas. None had any clinical feature of acromegaly preoperatively or when re-examined retrospectively. Only one patient had a clinically silent GH adenoma with a high serum IGF-1 (1083 μg/L). Six patients had a completely silent adenoma (normal IGF-1, mean 223 μg/L, range from 94 to 376 and/or basal GH below 1 μg/L). PRL immunostaining was also present in three, ACTH in two and glycoproteins in one. Silent somatotroph adenomas thus represent 9% of somatotroph adenomas in our series.

Conclusion : Silent somatotroph adenomas may be more prevalent than previously considered.

1) Wade AN et al , Eur J Endocrinol 2011, 165, 39-44

Disclosure: AL: Investigator, Novartis Pharmaceuticals, Editor, Up To Date, Consultant, Novartis Pharmaceuticals. SV: Investigator, Novartis Pharmaceuticals, Research Funding, Serono. Nothing to Disclose: VP, FB, IB, CB, CG, OS

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