Pituitary hyperplasia refers to the diffuse pituitary enlargement that can be physiological in young menstruating females or pregnant/lactating women or, less commonly, secondary to end-organ failure.
The upper limit of normal pituitary height varies with age and gender 1:
- infants, children: 6 mm
- males and postmenopausal women: 8 mm
- young menstruating females: 10 mm
- pregnant/lactating women: 12 mm
Non-physiologic pituitary hyperplasia is commonly caused by an end-organ failure such as hypothyroidism 3, Addison disease 4 and neuroendocrine tumors 5. Medications such as estrogen, GnRH analogs and antipsychotics can cause or exacerbate pituitary hyperplasia 5.
The pituitary gland can be assessed both by CT and MRI dedicated protocols, which can show the following: 1
- enlarged homogeneously enhancing pituitary gland with a convex superior margin
- size : >10 mm up to 15 mm
- maybe globular/nodular, mimicking pituitary adenoma
Treatment and prognosis
Only surveillance is suggested until reversal of the underlying pathological condition as pituitary hyperplasia rarely progresses 5.
- 1. Osborn AG, Salzman KL, Barkovich AJ. Diagnostic Imaging. Lippincott Williams & Wilkins. (2009) ISBN:1931884722. Read it at Google Books - Find it at Amazon
- 2. Elster AD, Sanders TG, Vines FS et-al. Size and shape of the pituitary gland during pregnancy and post partum: measurement with MR imaging. Radiology. 1991;181 (2): 531-5. doi:10.1148/radiology.181.2.1924800 - Pubmed citation
- 3. Shivaprasad KS, Siddardha K. Pituitary Hyperplasia from Primary Hypothyroidism. (2019) The New England journal of medicine. 380 (8): e9. doi:10.1056/NEJMicm1805378 - Pubmed
- 4. Agrawal A, Diwan SK. Pituitary hyperplasia resulting from primary hypothyroidism. Asian J Neurosurg. 2011;6 (2): 99-100. doi:10.4103/1793-5482.92171 - Free text at pubmed - Pubmed citation
- 5. De Sousa SM, Earls P, McCormack AI. Pituitary hyperplasia: case series and literature review of an under-recognised and heterogeneous condition. Endocrinology, diabetes & metabolism case reports. 2015: 150017. doi:10.1530/EDM-15-0017 - Pubmed