statdx/docs_md/articles/pituitary-hyperplasia_9696bc9e-f00b-4fa7-aa67-f039efd8fbed.md

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Pituitary Hyperplasia	9696bc9e-f00b-4fa7-aa67-f039efd8fbed	key value 5cff4116-3654-4b3a-bb75-5ebe0b8c9850 Anne G. Osborn, MD, FACR	name slug treeNodeId Brain brain 6d8829f1-14d7-45af-8675-255189aa526a name slug treeNodeId Diagnosis diagnosis 51c00394-446e-4a38-94af-d3b1d14d34e8 name slug treeNodeId Anatomy-Based Diagnoses anatomy-based-diagnoses 529d3e33-f508-498c-bc70-cf962e81e629 name slug treeNodeId Sella and Pituitary sella-and-pituitary 9afaeeb6-661c-49be-b55f-5bdc1c98a53e name slug treeNodeId Miscellaneous miscellaneous 7941c33d-0063-41a2-b035-39440c09b829 name slug treeNodeId Pituitary Hyperplasia pituitary-hyperplasia null	Brain	10eb0985-d56e-4149-91b4-be614f820dd7	6f43163b-2ff5-428a-a535-d0b805a74a43	12	06/08/20	Pituitary Hyperplasia	Brain, Diagnosis, Anatomy-Based Diagnoses, Sella and Pituitary, Miscellaneous, Pituitary Hyperplasia	Pituitary Hyperplasia | STATdx	Pituitary Hyperplasia	DX	true	Brain Diagnosis Anatomy-Based Diagnoses Sella and Pituitary Miscellaneous Pituitary Hyperplasia

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title: "Pituitary Hyperplasia" docid: "9696bc9e-f00b-4fa7-aa67-f039efd8fbed" authors:

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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

  • May be indistinguishable
  • Rare: May occur secondary to primary hypothyroidism

• Pituitary Microadenoma

  • May be indistinguishable
  • Enhances slower than normal gland on dynamic study

• Lymphocytic Hypophysitis

  • Enlarged gland &/or stalk
  • Pregnant or postpartum females

• Venous Congestion

  • Can occur with intracranial hypotension
  • Dural arteriovenous fistulas

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
2. Takayasu S et al: Presence of aberrant adrenocorticotropic hormone precursors in two cases of McCune-Albright syndrome. Endocr J. 67(3):353-9, 2020
3. 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
4. Kinoshita Y et al: Physiologic pituitary hyperplasia causing visual disturbance during adolescence. J Clin Neurosci. 61:279-81, 2019
5. Shivaprasad KS et al: Pituitary hyperplasia from primary hypothyroidism. N Engl J Med. 380(8):e9, 2019
6. Shukla P et al: Pituitary hyperplasia in severe primary hypothyroidism: a case report and review of the literature. Case Rep Endocrinol. 2019:2012546, 2019
7. Biswas SN et al: Physiological pituitary hyperplasia misinterpreted and treated as lymphocytic hypophysitis. BMJ Case Rep. 2018, 2018
8. 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
9. Nachawi N et al: Pituitary 'pseudotumor': an under-recognised complication of undertreated primary hypothyroidism. BMJ Case Rep. 2018, 2018

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

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.