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pituitary adenoma/GH secreting (somatotrophinoma)
Also see acromegaly.
Genetics:
1) mutations in Gs-alpha gene (GNAS1 {gsp}) chromosome 20q13.2 (R201 -> C or H; G227 -> R)
2) 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:
1) trans-sphenoidal surgery
-> tumor recurrence is 5-20% depending upon size (larger tumors being more likely to recur)
2) standard supervoltage radiation
a) remission in most patients
b) radiation effect achieved over period of 2 years
c) at 5 years, 50% of patients have deficiencies of other trophic hormones
3) persistent symptoms of acromegaly after surgery
a) octreotide or cabergoline
b) pegvisomant may be alternative
Related
acromegaly
gsp proto-oncogene (GNAS1)
sella turcica (hypophyseal fossa)
somatotropin; growth hormone; somatropin (GH)
General
pituitary adenoma
Properties
SIGN/SYMPTOM: acromegaly
Database Correlations
OMIM 102200
References
- Medical Knowledge Self Assessment Program (MKSAP) 11, 15, 18.
American College of Physicians, Philadelphia 1998, 2009, 2018.