pituitary adenoma/GH secreting (somatotrophinoma)

Introduction

Also see acromegaly.

Genetics

• mutations in Gs-alpha gene (GNAS1 {gsp}) chromosome 20q13.2 (R201 -> C or H; G227 -> R)
• associated with defects in AIP

Clinical manifestations

• increased hand & foot size, increased spacing of teeth
• see acromegaly

Laboratory

• growth hormone suppression test
  • failure of oral glucose to suppress serum GH is consistent with acromegaly

Radiology

• MRI of the sella turcica to determine tumor size

Differential diagnosis

• rare abdominal or chest tumor secreting ectopic GHRH

Management

• trans-sphenoidal surgery
  • tumor recurrence is 5-20% depending upon size (larger tumors being more likely to recur)
• standard supervoltage radiation
  • remission in most patients
  • radiation effect achieved over period of 2 years
  • at 5 years, 50% of patients have deficiencies of other trophic hormones
• persistent symptoms of acromegaly after surgery
  • octreotide or cabergoline
  • pegvisomant may be alternative

More general terms

• pituitary adenoma

Additional terms

• acromegaly
• gsp proto-oncogene (GNAS1)
• sella turcica (hypophyseal fossa)
• somatotropin; growth hormone; somatropin (GH)

Database

• OMIM: https://mirror.omim.org/entry/102200