Pituitary gland

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The pituitary gland is known as the master gland.

Divisions:[1]

  • Anterior pituitary (AKA adenohypophysis).
  • Posterior pituitary (AKA neurohypophysis, neural pituitary).

Function

Anterior

Hormones:[2]

  • Growth hormone (GH).
  • Luteinizing hormone (LH)
  • Follicle-stimulating hormone (FSH)
  • Thyroid stimulating hormone (TSH)
  • Adrenocorticotropic hormone (ACTH)
  • Prolactin (PRL)

Mnemonic: "Go Look For The Adenoma Please" = GH, LH, FSH, TSH, ACTH, PRL.

Posterior

Hormones:[2]

  • Oxytocin.
  • Antidiuretic hormone (ADH).

Anatomy and histology

Anatomy

Basic anatomy (simplified):[3]

  • Anterior:
    • Pars distalis.
    • Pars intermedia.
  • Posterior:
    • Pars nervosa.

Embryological origin:[3]

  • Anterior - Rathke's pouch (roof of mouth).
  • Posterior - diencephalon (ventral aspect).

Images:

Histology

Anterior

  • Acidophils (40% of cells) = red or orange.
    • GH, PRL.
  • Basophils (10% of cells) = basophilic (light blue).
    • TSH, LH, FSH.
  • Chromophobes (50% of cells) = amphophilic (purplish/grey).

Notes:

  • The cellular product (i.e. hormone produced) is not strictly correlated with the cell type.[4]

Posterior

Features:[4]

  • Herring bodies - key feature.
    • Eosinophilic axonal dilations filled with lysosomes and neurosecretory granules.
  • Less cellular.
    • Usually more cellular in perivascular location.

Image: Herring bodies (ouhsc.edu).

DDx for stellar lesions

  • Pituitary adenoma.
  • Rathke cleft cyst.
  • Craniopharyngioma.
  • Germ cell tumour.
  • Meningioma.

Pituitary adenoma

General

  • Classically presents with visual field defects.

Microscopic

Features:[5]

  • Loss of fibrous stroma.

Rathke cleft cyst

See Head and neck pathology.
  • Arises from intermediate lobe.
  • Embryonic remnant.
  • Related to craniopharyngioma.

Craniopharyngioma

See Head and neck pathology.
  • Related to Rathke cleft cyst.

Necrosis

  • Rare.

Causes

  • Sheehan syndrome - secondary to blood loss in childbirth.[6]
  • Syphilis (fetal-maternal transmission).[7]
  • Mollaret's meningitis - very rare.[8] (???)
  • Spontaneous necrosis of pituitary tumours - case reports.[9]

Autoimmune hypophysitis

General

Features:[10]

  • Rare.
  • Autoantigens are unknown.
  • May be misdiagnosed as a nonsecreting adenoma.

Microscopic

Features:[10]

  • Lymphocytic infiltration.

See also

References

  1. http://www.vivo.colostate.edu/hbooks/pathphys/endocrine/hypopit/histo.html
  2. 2.0 2.1 http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/Pituitary.html
  3. 3.0 3.1 URL: http://www.vivo.colostate.edu/hbooks/pathphys/endocrine/hypopit/histo_pit.html. Accessed on: 31 October 2010.
  4. 4.0 4.1 Perry, Arie; Brat, Daniel J. (2010). Practical Surgical Neuropathology: A Diagnostic Approach: A Volume in the Pattern Recognition series (1st ed.). Churchill Livingstone. pp. 26. ISBN 978-0443069826.
  5. Perry, Arie; Brat, Daniel J. (2010). Practical Surgical Neuropathology: A Diagnostic Approach: A Volume in the Pattern Recognition series (1st ed.). Churchill Livingstone. pp. 36. ISBN 978-0443069826.
  6. URL: http://www.mayoclinic.com/health/sheehans-syndrome/DS00889. Accessed on: 16 November 2010.
  7. URL: http://pediatrics.aappublications.org/cgi/content/full/104/1/e4. Accessed on: 16 November 2010.
  8. Dancer CM, Woods ML, Henderson RD, Robertson T, Mungomery M, Allworth A (July 2008). "Mollaret's meningitis and pituitary failure associated with a Rathke's cleft cyst". Intern Med J 38 (7): 609–11. doi:10.1111/j.1445-5994.2008.01709.x. PMID 18715308.
  9. Sachdev Y, Evered DC, Hall R (April 1976). "Spontaneous pituitary necrosis". Br Med J 1 (6015): 942. PMC 1639254. PMID 1268492. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1639254/pdf/brmedj00512-0028a.pdf.
  10. 10.0 10.1 Tzou SC, Lupi I, Landek M, et al. (July 2008). "Autoimmune hypophysitis of SJL mice: clinical insights from a new animal model". Endocrinology 149 (7): 3461–9. doi:10.1210/en.2007-1692. PMC 2453094. PMID 18388197. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2453094/.

External links