Somatotroph Adenomas

Question 1

What is the second most common cause of functioning pituitary adenoma?

Answer 1

Growth hormone–secreting somatotroph adenomas

Question 2

How does this tumor manifest?

Answer 2

• Gigantism in children
• Acromegaly in adults
• Diabetes mellitus
• Gonadal dysfunction
• Generalized muscle weakness
• Hypertension
• Arthritis
• Congestive heart failure
• Increased risk for gastrointestinal cancers

Question 3

When/How is tumer discovered?

Answer 3

Since the clincal manifestation is quite subtle and takes longt time, the tumor might be larg by the time it gets discovered

Question 4

What do we see in microscopic examination?

Answer 4

Densely or sparsely granulated cells, and immunohistochemical staining demonstrates growth hormone within the cytoplasm of the neoplastic cells. Small amounts of immunoreactive prolactin often are present as well.

Question 5

What does persistent growth hormone excess cause?

Answer 5

• Stimulates the hepatic secretion of insulin-like growth factor 1 (IGF1)→Which together with the growth hormones causes overgrowh of bones and muscles
• Associated with metabolic abnormalities→DM

Question 6

How does it manifest if the tumor develops before the epiphyses closes?

Answer 6

IGF1 and growth hormones⇒ Gigantism, the child will have increased body size with disproportionately long arms and legs

Question 7

How does it manifest if the tumor develops after the epiphyses closes?

Answer 7

If the IGF1 and growth hormones increases after the epiphyses is closed⇒ Acromegaly, in which growth is seen in soft tissue, skin, viscera, and the bones of the face, hands, and feet. In mos cases acromegaly is also seen in kids with gigantism