What is the recommended hormone evaluation for patients with suspected pituitary adenoma?

Recommended Hormone Evaluation for Suspected Pituitary Adenoma

For patients with suspected pituitary adenoma, a comprehensive evaluation of all anterior pituitary hormone axes is strongly recommended due to the high prevalence of hypopituitarism (37-85%) in these patients. 1

Core Hormone Evaluation

• Complete anterior pituitary axis assessment is necessary as panhypopituitarism occurs in 6-29% of patients with pituitary adenomas 1, 2
• Prolactin testing should be performed in all patients to rule out hypersecretion that might not be clinically suspected (level II recommendation) 1
• Insulin-like growth factor 1 (IGF-1) evaluation is recommended to rule out growth hormone hypersecretion that might not be clinically suspected (level III recommendation) 1
• Thyroid function tests including TSH and free T4 to assess for central hypothyroidism, which occurs in 8-81% of patients 1
• Adrenal axis evaluation with morning cortisol and ACTH to assess for adrenal insufficiency, which occurs in 17-62% of patients 1
• Gonadal axis assessment with LH, FSH, and sex steroids (testosterone in men, estradiol in women) to evaluate for hypogonadism, which occurs in 36-96% of patients 1

Prevalence of Hormonal Deficiencies

• Growth hormone deficiency is the most common deficiency (61-100% of patients) 1, 2
• Hypogonadism is the second most common deficiency (36-96% of patients) 1, 2
• Adrenal insufficiency occurs in 17-62% of patients 1, 2
• Central hypothyroidism occurs in 8-81% of patients 1, 2
• Diabetes insipidus is uncommon, occurring in only about 7% of patients at presentation 1

Additional Testing for Specific Adenoma Types

• For suspected TSH-secreting adenomas: Measure TSH, free T4, and free T3 levels (TSHomas present with elevated or normal TSH with elevated free T4 and free T3) 3
• For suspected GH-secreting adenomas: IGF-1 and growth hormone levels with oral glucose tolerance test 4, 5
• For suspected ACTH-secreting adenomas: Late-night salivary cortisol, 24-hour urinary free cortisol, and low-dose dexamethasone suppression test 4, 5

Preoperative Considerations

• Replacement for adrenal insufficiency and significant hypothyroidism is recommended in all patients preoperatively (level II recommendation) 1
• Adrenal insufficiency must be addressed first before treating other hormonal deficiencies to avoid precipitating an adrenal crisis 6

Clinical Pearls and Pitfalls

• Hyperprolactinemia is seen in 25-65% of patients with pituitary adenomas, with a mean level of 39 ng/mL 1
• Only a minority of patients with nonfunctioning pituitary adenomas exceed a serum prolactin level of 200 ng/mL 1
• Patients with 3 or more pituitary hormone deficiencies are more likely to have GH deficiency and may not need dynamic testing 2
• No evidence supports routine biomarker testing (e.g., α-subunit or chromogranin A) or genetic testing in patients with sporadic nonfunctioning pituitary adenomas 1
• Genetic assessment should be offered to all children and young people with pituitary adenomas, especially those with growth hormone and prolactin excess 2, 3

By following this comprehensive hormone evaluation approach, clinicians can accurately diagnose pituitary adenomas, identify hormone deficiencies requiring replacement, and determine the appropriate treatment strategy to improve patient outcomes.