Testing to Diagnose Hormone-Secreting Pituitary Tumors

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Pituitary adenomas account for approximately 15% of intracranial tumors. Management of these benign tumors requires diagnosis of the specific intrasellar disease and comprehensive, multidisciplinary treatment of local mass effects and peripheral endocrinopathies. Since tumors can produce different hormones, their consequences and management vary widely.

Testing to Diagnose Hormone-Secreting Pituitary Tumors

Tumor or Disease Test Results Requiring Further Evaluation
Prolactinoma Serum prolactin level measurement Prolactin level elevated
Acromegaly Serum insulin-like growth factor 1 (IGF-1) level Age-adjusted IGF-1 level elevated
Oral glucose-tolerance test (75 g of glucose) with growth hormone measured at 0, 30, and 60 min Growth hormone level >0.4 μg/liter with the use of an ultrasensitive assay
Cushing’s disease 24-hr urinary free cortisol measurement Elevated urinary free cortisol level on at least two tests
Midnight salivary cortisol measurement Elevated free salivary cortisol level
Plasma cortisol measurement at 8 a.m., after administration of dexamethasone (1 mg) at 11 p.m. Failure to suppress cortisol level to <1.8 μg/dl
Serum corticotropin measurement Low corticotropin level suggests adrenal adenoma; very high level may indicate ectopic corticotropin source
Thyrotropin-secreting tumor Serum thyrotropin measurement, free T4 measurement Normal or increased free T4 level with measurable thyrotropin may suggest thyrotropin-secreting tumor

 

 

References:

  1. Melmed S. Pituitary-Tumor Endocrinopathies. N Engl J Med. 2020;382(10):937‐950. [Medline]
  2. Borg A, Jaunmuktane Z, Dorward N. Tumors of the Neurohypophysis: One Unit’s Experience and Literature Review. World Neurosurg. 2020;134:e968‐e978. [Medline]

Created May 15, 2020.