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Pituitary Incidentalomas

Chanson, Philippe MD*; Young, Jacques MD, PHD†

CME Review Articles: Neuroendocrinology
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Improvements in diagnostic imaging techniques during the past several years have led to an increasing recognition of asymptomatic lesions in the pituitary. The management of these “pituitary incidentalomas” is controversial. Some lesions may increase in size, causing impaired pituitary hormone production or compressed optic chiasm, whereas others will remain unchanged in size and will never produce tumoral or hormonal symptoms. The type of initial endocrinological assessment and the required frequency and length of follow-up need to be carefully determined, taking cost-effectiveness into account. In this setting, it is crucial to obtain precise information about the natural history of each type of pituitary lesion. Incidental discovery of an intrapituitary cyst is frequent and needs careful examination of magnetic resonance (MR) images to differentiate between craniopharyngiomas (in which association with solid component and calcification is more likely) and Rathkes cleft cyst (in which cyst size is generally less than 20 mm and which is less frequently associated with hypopituitarism on hormonal evaluation).

Incidental microadenomas (≤10 mm) raise the issue of the importance of the hormonal evaluation, given the high prevalence of lesions less than 10 mm in size and the rarity of hormone secretion by these microincidentalomas. If a careful history and physical examination rules out acromegaly and Cushings disease, the hormonal work-up can probably be limited to prolactin measurement for diagnosis of prolactinoma. Thereafter, given the natural history of these nonsecreting microadenomas and the fact that they very rarely increase in size, a “wait-and-see” attitude may be recommended.

The incidental discovery of a macroadenoma (> 10 mm) requires an extensive work-up. If the lesion compresses the optic nerves, surgical removal is obviously indicated. If the lesion causes hypersecretion of prolactin, growth hormone or corticotropin, patients may be offered tumor-subtype directed therapy. On the contrary, if no hormonal hypersecretion (or secretion limited to gonadotropins and/or their subunits) is found, and if the macroadenoma is some distance from the optic chiasm, routine surgical removal of the tumor may not be necessary. Indeed, in prospective studies of incidental macroadenomas, only 25% increased in size and less than 5% required an operation. If expectant management is elected, yearly MRI surveillance may be recommended, at least during the first 5 years.

Another frequent incidentaloma is the normal pituitary hypertrophy found in young women. Careful examination of MR images may help to distinguish it from pituitary tumors and infiltrating lesions and to avoid unnecessary surgery.

Learning Objectives:

* Explain how to recognize and manage young women whose pituitary “incidentaloma” may represent physiological hypertrophy.

* Distinguish between the two major causes of asymptomatic cystic pituitary lesions.

* Identify appropriate evaluative measures and management for patients having an asymptomatic pituitary microadenoma.

* Describe the criteria used to decide between surgery and nonoperative management in patients presenting with an asymptomatic pituitary macroadenoma.

*†Professor of Endocrinology, Univeristy of Paris XI, Paris, France. *Head and †Physician, Division of Endocrinology and Reproductive Diseases, Bicêtre University Hospital, Le Kremlin Bicêtre, France.

Chief Editor’s Note: This article is the 10th of 36 that will be published in 2003 for which a total of up to 36 Category 1 CME credits can be earned. Instructions for how credits can be earned appear following the Table of Contents.

Address correspondence and reprints requests to: Philippe Chanson, MD, Service d’Endocrinologie et des Maladies de la Reproduction, Hôpital Bicêtre, 78 rue du Général Leclerc, F-94275 Le Kremlin-Bicêtre, France. E-mail: pchanson@club-internet.fr

The authors have disclosed that they have no significant relationship with or financial interest in any commercial company pertaining to this educational activity.

© 2003 Lippincott Williams & Wilkins, Inc.