21. Anterior lobe pituitary tumors and their consequences. Posterior lobe syndromes. Disorders associated with hypopituarism (Sheehan syndrome, chromophobic adenoma, empty sella syndrome, suprasellar tumors)

What are the different cells of the anterior pituitary?

- Chromophobe cells

- Chromophile cells

-> Acidophilic cells

-> Basophilic cells

How can we divide the acidophilic cells? which hormones do they produce?

- Somatotrophs -> produce growth hormone

- Lactotrophs -> produce prolactine

How can we divide the basophilic cells? which hormones do they produce?

- Corticotrophs -> produce ACTH

- Thyrotrophs -> produce TSH

- Gonadotrophs -> produce FSH, LH

Anterior lobe tumors pituitary tumors are associated with?

Multiple endocrine neoplasia type 1

How can we classify the anterior lobe pituitary tumors?

- Whether they produce hormones or not

-> Which hormones they produce

- Whether they are larger or smaller than 1cm

Tumors that produce hormones?

Functional/secretory adenomas

Tumors that doesnt produce hormones?

- Non-functional/Non-secretory

- Chromophobe adenoma

Most pituitary tumors are?

Non-functional/Non-secretory

Tumors larger than 1 cm?

Macroadenomas

Tumors smaller than 1 cm?

Microadenomas

Functional tumors of the pituitary gland?

- Prolactinoma/ prolactin cell adenoma

- Somatotroph adenoma/ growth hormone cell adenoma

- Corticotroph adenoma

- Thyrotroph adenoma

- Gonadotroph adenoma

Prolactinoma associated syndrome or symptoms?

- Galactorrhoea

- Amenorrhoea

- Sexual dysfunctions

- Infertility

Somatotroph adenoma associated syndrome or symptoms?

- Gigantism in children

- Acromegaly in adults

Corticotroph adenoma associated syndrome or symptoms?

Cushings disease

Thyrotroph adenoma associated syndrome or symptoms?

Secondary hyperthyroidism

Gonadotroph adenoma associated syndrome or symptoms?

Hypogonadism

What is it called when an adenoma produce more than one hormone?

Plutihormonal adenomas

- very rare

Functional pituitary adenomas will cause?

Hyperpituitarism

Non-functional pituitary adenomas will cause? why?

Hypopituitarism

- A non-functional adenoma produce fewer symptoms, which allows them to grow larger before they are treated = macroadenomas

- As they grow, they will obliterate the rest of the pituitary

Which hormones are secreted from the posterior pituitary?

The posterior pituitary doesnt produce any hormones itself, only secretes them

- ADH

- Oxytocin

Where are ADH and oxytocin produced?

Hypothalamus

Posterior pituitary syndromes?

Clinically relevant posterior pituitary syndromes involve abnormalities of ADH production

- Central diabetes insipidus

- Syndrome of inappropriate ADH secretion

What is central diabetes insipidus?

ADH deficiency

- renal tubules lose their ability to reabsorb water

What will central diabetes insipidus lead to?

- Polyuria

- Hypovolemia

What may be the cause of central diabetes insipidus?

- Idiopathic

- Brain tumors, compressing the posterior pituitary

- Traumatic brain injuries

Syndrome of Inappropriate Antidiuretic Hormone (SIADH)?

Excessive production of ADH

What usually cause syndrome of inappropriate ADH?

Usually caused by ADH producing tumors

- especially small cell lung cancer, as a paraneoplastic syndrome

Syndrome of inappropriate AHD can lead to?

Normovolemic hyponatraemia

What is hypopituitarism?

The inadequate production of one or more anterior pituitary hormones

- occurs due to damage to the pituitary

What is it called if the secretion of both anterior and posterior pituitary hormones are affected?

Panhypopituitarism

What are the special sequence that the different pituitary hormones are lost??

- GH

- FSH, LH

- Prolactin

- TSH

- ACTH

Most important causes of hypopituitarism?

- Non-functional pituitary macroadenomas

- Pituitary apoplexy

-> Sheehan syndrome

-> Traumatic brain injury

- Infiltration of the pituitary or hypothalamus

-> Heamochromatosis

-> Meningitis

-> Tuberculosis

What is Sheehan syndrome?

Ischaemic necrosis of the pituitary due to blood loss during or after childbirth

- first symptom is that the mother cant lactate, due to the prolactin deficiency

What is Empty sella syndrome?

Condition where the pituitary gland is shrunk or flattened - causing the sella turcica to be filled with CSF instead

- idiopathic cause

- pituitary apoplexy

- surgical removal

Suprasellar tumors?

Tumors that are above the sella turcica, in the suprasellar cistern

- the infundibulum lies in the cistern, so this tumor can cause hypopituitarism or panhypopituitarism

Which tumors may occur suprasellarly?

- Craniopharyngoma

- Glioma

- Lipoma

- Rathkes cyst