Date post: | 19-Dec-2015 |
Category: |
Documents |
View: | 229 times |
Download: | 2 times |
Pituitary GlandPituitary Gland
The normal microscopic appearance of the pituitary gland
The normal microscopic appearance of the pituitary gland
The adenohypophysis
The adenohypophysis
The neurohypophysis
The adenohypophysis contains three major cell types:
Cell types and functionCell types and function
• Somatotroph GH
• Mammotroph Prl
• Corticotroph ACTH
• Gonadotroph LH , FSH
• Thyrotroph TSH
• Null cells non-function
Hyperpituitarism - AdenomaHyperpituitarism - Adenoma
• Excess hormone production by the anterior lobe majority are Adenomas
• Hyperplasia and carcinoma are rare
Morphology of AdenomaMorphology of Adenoma
• Single and encapsulated• Microadenoma is lesser than 1 cm• Macroadenoma is larger than 1 cm , may reach
up to 10 cm• May show cystic changes and foci of necrosis • Expand sella tursica pressure effects (optic
chaisma )
• Pituitary apoplexy = haemorrage in the adenoma
HistologyHistology
Sheets of uniform rounded cells with delicate scanty stroma
Immunohistochimistry : Type of secertory hormone
Types of Pitutary adenomaTypes of Pitutary adenoma
Growth hormone producing Growth hormone producing adenoma (5%)adenoma (5%)
• Usually large
• Evenly distributed into densely and sparsely granulated types
• E/M spherical cytoplasmic granules
• Immuno positive GH - Gh 1/3 and PRL
• Acidophilic cells
Growth hormone producing adenoma (5%)
• Gigantism (children)
• Acromegaly (adults)
• glucose intolrence , DM,osteoprosis, hypertension
Prolactin producing adenoma Prolactin producing adenoma (20-30%)(20-30%)
• The most common functioning adenoma • Majority are microadenamas and sparsely
granulated • E/M : small secretory granules • Immuon:+sv PRL• Women ---- microadenomas (amenorrhoea,
glactorrhea syndrom )• Men and old females ------ macroadenoam(late
discovery)-----mass effect
Non secretory (Null cell ) adenoma Non secretory (Null cell ) adenoma (20%)(20%)
• Commenest cause of hypopituitarism
• Large ( macroadenoma) with atrophy of the surrounding pituitary tissue
• Immuno Variable 1/3 negative
• Chromphobic cells
Other rare types of adenomasOther rare types of adenomas
• ACTH producing adenoma
• FSH and LH – producing adenoma
• TSH-Producing adenoma
• Mixed
ACTH producing adenomaACTH producing adenoma
• Usually microadenomas
• Give rise to Cushing’s disease
• E/M: +ve ACTH
• Basophilic cells
• Nelson’syndrome(bilatral adrenalectomy----secondry ACTH- producing pituitary adenoma
FSH and LH – producing adenomaFSH and LH – producing adenoma
• Usually large
• No clinical features due to FSH and LH \
• Mass effect
• High serum FSH and Lh
• E/M : secretary granules( 250 nm)
• Immuno : +ve FSH and LH
• Basophile cells
TSH-Producing adenomaTSH-Producing adenoma
• Rare
• Produce TSH
Carcinoma of the pituitaryCarcinoma of the pituitary
• Rare and non functioning• Differentaited from adenoma by metastasis
HypopituitarismHypopituitarism
• Causes:
• Non_secrertory adenoma
• Pituitary necrosis (sheehan’s syndrom)
• The empty sella syndrome• Pituiraty destruction (infection,
radiation,surgical ablation,metastasis,vasculitis)
• Clinical features :
• Deficiency of Gh : Dwarfism (children)
• Deficiency of Gonadotrophins : stereility
• Deficiency of ACTH or TSH : Hypofunction of the relevant endocrine glande
Posterior pituitary syndromesPosterior pituitary syndromes
• Rare
• Due to hypothalamic tumors (gliaoma,gangliocytoma,craniopharyngioma,GCT)
• Deficiency of antidiuretic hormone (ADH Deficiency)----- diabetes insipidus pyolyuria=polydipsia