Normal Pituitary

Epidemiology and Etiology:

• .

Common sites:

• Sella turcica 
• Close proximity to optic chiasm

Gross features:

•  0.5g
• Enlarges during pregnancy
• Yellow-tan
• Firm (compared to adenoma)
• Anterior lobe (adenohypophysis) (80% of gland)
• Posterior lobe (neurohypophysis)

Histologic features:

• Acidophil (eosinophilic)
• Somatotrophs – half of hormone-producing cells
• lactotrophs
• Basophil
• Corticotrophs
• Thyrotrophs (pale basophilic)
• Gonadotrophs
• Chromophobe (poorly-staining)
• Posterior (neurohypophysis):
• Pituicytes – modified glial cells

Immunophenotype:

Marker:	Sensitivity:	Specificity:
GH (somatotrophs)
Prolactin (lactotrophs)
ACTH (corticotrophs)
POMC (corticotrophs) (Pro-opiomelanocortin)
MSH (corticotrophs) (melanocyte-stimulating hormone)
Endorphins (corticotrophs)
Lipotropin (corticotrophs)
TSH (thyrotrophs)
LH (gonadotrophs)
FSH (gonadotrophs)
ADH (neurons of hypothalamus)
Oxytocin (neurons of hypothalamus)

Molecular features:

•  .

Other features:

• Hypothalamic hormones:
• TRH –> + TSH
• Dopamine -> (-) prolactin
• CRH -> + ACTH
• GHRH -> + GH
• GIH (somatostatin) -> (-) GH
• GnRH -> + FSH/LH

References:

•  Robbins & Cotran Pathologic Basis of Disease (2005)