---
title: "Pituitary Hyperplasia"
docid: "9696bc9e-f00b-4fa7-aa67-f039efd8fbed"
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- key: "5cff4116-3654-4b3a-bb75-5ebe0b8c9850"
value: "Anne G. Osborn, MD, FACR"
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pageDescription: "Pituitary Hyperplasia"
pageKeywords: "Brain, Diagnosis, Anatomy-Based Diagnoses, Sella and Pituitary, Miscellaneous, Pituitary Hyperplasia"
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breadcrumbs:
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---
# KEY FACTS
- ## Terminology
- Normal maximal pituitary height varies with age, sex
- Pregnant/lactating females: 12 mm
- Young menstruating females: 10 mm
- Males, postmenopausal females: 8 mm
- Infants, children: 6 mm
- Nonphysiologic hyperplasia seen with
- Hypothyroidism, Addison disease, or other end-organ failure
- Some neuroendocrine neoplasms
- ## Imaging
- Enlarged homogeneously enhancing pituitary gland with convex superior margin
- Best technique: High-resolution MR
- Sagittal/coronal T1; coronal T2
- Dynamic coronal T1WI
- Postcontrast T1 FS sagittal/coronal T1
- 3- to 4-mm slice thickness
- ## Top Differential Diagnoses
- Pituitary macroadenoma
- Pituitary microadenoma
- Lymphocytic hypophysitis
- Venous congestion (intracranial hypotension, dural arteriovenous fistula)
- ## Pathology
- Normal: Physiologic hyperplasia in pregnancy, lactation
- Abnormal: Longstanding untreated primary hypothyroidism
- Loss of thyroxine feedback inhibition, overproduction of thyrotropin-releasing hormone
- Secondary pituitary hyperplasia
- Orthotopic or ectopic production of hypothalamic-releasing hormones
- Orthotopic: Response to end-organ failure
- Ectopic: Related to neuroendocrine tumors
# TERMINOLOGY
- ## Definitions
- Upper limit of normal pituitary height varies with age, sex
- Pregnant/lactating females: 12 mm
- Young menstruating females: 10 mm
- Males, postmenopausal females: 8 mm
- Infants, children: 6 mm
- Nonphysiologic pituitary hyperplasia seen with
- Longstanding untreated primary hypothyroidism
- Addison disease, end-organ failure, some neuroendocrine neoplasms
# IMAGING
- ## General Features
- ### Best diagnostic clue
- Enlarged homogeneously enhancing pituitary gland with convex superior margin
- > 10 mm up to 15 mm
- May be nodular, mimic pituitary adenoma
- ### Location
- Sella; may extend into suprasellar region, compress adjacent structures
- ## CT Findings
- ### NECT
- Noncalcified pituitary gland enlargement
- ### CECT
- Homogeneous enhancement
- ## MR Findings
- ### T1WI
- Isointense with remainder of pituitary gland
- ### T2WI
- Isointense with remainder of pituitary gland
- ### T1WI C+
- Diffusely enhancing gland is typical
- Rare = may cause focal nodular enlargement
- Dynamic MR: Enhances similar to remainder of gland
- ## Imaging Recommendations
- ### Best imaging tool
- MR with 3- to 4-mm slices, small FOV
- ### Protocol advice
- Sagittal/coronal T1; coronal T2
- Dynamic enhanced coronal T1WI
- Postcontrast T1 FS sagittal/coronal
# DIFFERENTIAL DIAGNOSIS
- [Pituitary Macroadenoma](/document/pituitary-microadenoma/283f3068-d369-4f79-bf01-0f2b82c6e49b)
- May be indistinguishable
- Rare: May occur secondary to primary hypothyroidism
- [Pituitary Microadenoma](/document/pituitary-microadenoma/283f3068-d369-4f79-bf01-0f2b82c6e49b)
- May be indistinguishable
- Enhances slower than normal gland on dynamic study
- [Lymphocytic Hypophysitis](/document/lymphocytic-hypophysitis/f30774c3-cbd0-4ab3-b3d1-e0574106db1f)
- Enlarged gland &/or stalk
- Pregnant or postpartum females
- ## Venous Congestion
- [Can occur with intracranial hypotension](/document/intracranial-hypotension/818a7972-1032-4d3e-a65a-97c494334aac)
- [Dural arteriovenous fistulas](/document/dural-av-fistula/628fd160-1e22-4b55-83f9-c25464d05bd6)
# PATHOLOGY
- ## General Features
- ### Etiology
- Normal: Physiologic hyperplasia in pregnancy, lactation
- Longstanding untreated primary hypothyroidism
- Loss of thyroxine feedback inhibition, overproduction of thyrotropin-releasing hormone
- Secondary pituitary hyperplasia
- Orthotopic or ectopic production of hypothalamic-releasing hormones
- Orthotopic: Response to end-organ failure
- Ectopic: Related to neuroendocrine tumors
- ## Microscopic Features
- Nodular hyperplasia characterized by marked expansion of acini, architectural distortion
- Diffuse hyperplasia requires formal cell count
- Growth hormone cell hyperplasia usually diffuse, occurs with neuroendocrine tumors
- Pancreatic islet cell tumor, pheochromocytoma, and bronchial and thyroid carcinoid tumors
- Associated with McCune-Albright syndrome, multiple endocrine neoplasia syndrome, and Carney complex
- Prolactin cell hyperplasia: Diffuse > nodular
- May be seen with pregnancy and lactation, estrogen treatment, primary hypothyroidism, Cushing disease
- Corticotroph hyperplasia: Nodular or diffuse
- Associated with Cushing disease, neuroendocrine tumors, untreated Addison disease
- Thyrotroph hyperplasia
- Longstanding primary hypothyroidism, may have associated prolactin hyperplasia
- Gonadotroph hyperplasia (e.g., Turner, Klinefelter syndromes)
# CLINICAL ISSUES
- ## Presentation
- ### Most common signs/symptoms
- Varies with cell type of hyperplasia
- ## Demographics
- ### Age
- Typically adults (rare in children)
- ### Sex
- No predilection
- ## Treatment
- If related to hypothyroidism, regression after thyroid hormone therapy common
- Treat end-organ failure or neuroendocrine tumor
# DIAGNOSTIC CHECKLIST
- ## Consider
- Hyperplasia may mimic adenoma
- Clinical information can help differentiate
- If imaging looks like adenoma in prepubescent male, consider end-organ failure
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## References
# Selected References
1. [Du J et al: Pituitary adenoma secondary to primary hypothyroidism: two case reports. Medicine (Baltimore). 99(8):e19222, 2020](http://www.ncbi.nlm.nih.gov/pubmed/?term=32080117%5Bpmid%5D)
1. [Takayasu S et al: Presence of aberrant adrenocorticotropic hormone precursors in two cases of McCune-Albright syndrome. Endocr J. 67(3):353-9, 2020](http://www.ncbi.nlm.nih.gov/pubmed/?term=31801917%5Bpmid%5D)
1. [Cossu G et al: Comprehensive evaluation of rare pituitary lesions: a single tertiary care pituitary center experience and review of the literature. Endocr Pathol. 30(3):219-36, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=31209729%5Bpmid%5D)
1. [Kinoshita Y et al: Physiologic pituitary hyperplasia causing visual disturbance during adolescence. J Clin Neurosci. 61:279-81, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=30470648%5Bpmid%5D)
1. [Shivaprasad KS et al: Pituitary hyperplasia from primary hypothyroidism. N Engl J Med. 380(8):e9, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=30786191%5Bpmid%5D)
1. [Shukla P et al: Pituitary hyperplasia in severe primary hypothyroidism: a case report and review of the literature. Case Rep Endocrinol. 2019:2012546, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=31341683%5Bpmid%5D)
1. [Biswas SN et al: Physiological pituitary hyperplasia misinterpreted and treated as lymphocytic hypophysitis. BMJ Case Rep. 2018, 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=30139788%5Bpmid%5D)
1. [Cao J et al: Primary hypothyroidism in a child leads to pituitary hyperplasia: a case report and literature review. Medicine (Baltimore). 97(42):e12703, 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=30334955%5Bpmid%5D)
1. [Nachawi N et al: Pituitary 'pseudotumor': an under-recognised complication of undertreated primary hypothyroidism. BMJ Case Rep. 2018, 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=29950371%5Bpmid%5D)
## Images
### Selected Images
*Coronal graphic shows physiologic pituitary hyperplasia. The gland is uniformly enlarged and has a mildly convex superior margin.*
*Coronal graphic shows physiologic pituitary hyperplasia. The gland is uniformly enlarged and has a mildly convex superior margin.*
*Coronal graphic shows physiologic pituitary hyperplasia. The gland is uniformly enlarged and has a mildly convex superior margin.*
*Sagittal T1 C+ MR in a 38-year-old woman undergoing infertility treatment imaged for headache shows a homogeneously enhancing pituitary measuring 12 mm.*
*Sagittal T1 C+ MR in a 38-year-old woman undergoing infertility treatment imaged for headache shows a homogeneously enhancing pituitary measuring 12 mm.*
*Coronal T1 C+ MR shows typical physiologic pituitary hyperplasia in a 28-year-old lactating woman. The gland has a mildly convex superior margin and measures nearly 14 mm in height.*
*Coronal T1 C+ MR shows typical physiologic pituitary hyperplasia in a 28-year-old lactating woman. The gland has a mildly convex superior margin and measures nearly 14 mm in height.*
*At follow-up 1 year later, coronal T1 C+ MR reveals a normal appearance to the pituitary gland with interval resolution of the postpartum physiologic enlargement.*
*At follow-up 1 year later, coronal T1 C+ MR reveals a normal appearance to the pituitary gland with interval resolution of the postpartum physiologic enlargement.*
### Additional Images
. The gland measured 12 mm in height.](images/app.statdx.com_image_thumbnail_37ac44af-2b4c-471f-94e6-a8c22151e115_annotated_true_size_900_quality_90_67b7dcb8.jpg)
*Sagittal T1 MR in a 53-year-old hypothyroid female patient shows a rounded, upwardly convex pituitary gland . The gland measured 12 mm in height.*
*Sagittal T1 MR in a 53-year-old hypothyroid female patient shows a rounded, upwardly convex pituitary gland . The gland measured 12 mm in height.*
*Coronal T2 MR shows the upwardly convex pituitary gland is isointense with brain.*
*Coronal T2 MR shows the upwardly convex pituitary gland is isointense with brain.*
*Sagittal T1 C+ FS MR in the same case shows the enlarged pituitary gland enhances intensely and uniformly.*
*Sagittal T1 C+ FS MR in the same case shows the enlarged pituitary gland enhances intensely and uniformly.*
*Coronal T1 C+ FS MR obtained after dynamic contrast-enhanced imaging shows the pituitary gland enhances uniformly. This is physiologic pituitary hyperplasia as a response to hypothyroidism and does not represent an adenoma.*
*Coronal T1 C+ FS MR obtained after dynamic contrast-enhanced imaging shows the pituitary gland enhances uniformly. This is physiologic pituitary hyperplasia as a response to hypothyroidism and does not represent an adenoma.*
*Sagittal T1 C+ MR in a 19-year-old female patient shows a very rounded appearing pituitary gland . Although it appears somewhat enlarged, it measures only 8 mm in height. The bony sella are unusually shallow, giving the appearance of pituitary enlargement.*
*Sagittal T1 C+ MR in a 19-year-old female patient shows a very rounded appearing pituitary gland . Although it appears somewhat enlarged, it measures only 8 mm in height. The bony sella are unusually shallow, giving the appearance of pituitary enlargement.*
*Coronal CECT shows diffuse enlargement and enhancement of the pituitary gland with a convex margin in this 42 year old with ovarian failure.*
*Coronal CECT shows diffuse enlargement and enhancement of the pituitary gland with a convex margin in this 42 year old with ovarian failure.*
*Coronal T1 MR shows nodular hyperplasia and an upward convex margin of the pituitary gland in this patient with Cushing disease. The mild hypointensity is atypical.*
*Coronal T1 MR shows nodular hyperplasia and an upward convex margin of the pituitary gland in this patient with Cushing disease. The mild hypointensity is atypical.*
*Coronal T1 C+ MR in the same case shows diffuse enhancement of the hyperplasia, similar to the pituitary gland.*