Pituitary Adenoma
Pituitary adenomas are benign tumors of the pituitary gland found in approximately 10% of people on autopsy, though the vast majority never cause symptoms or require treatment. Clinically relevant adenomas produce symptoms either through hormone overproduction (prolactin, growth hormone, ACTH, TSH) or through mass effect compressing the normal pituitary, optic chiasm, or cavernous sinus.
Symptoms
Symptoms depend on the tumor type and size. Hormone-producing tumors cause the syndrome of their specific hormone excess (amenorrhea and galactorrhea for prolactinoma, acromegaly for GH adenoma, Cushing's disease for ACTH adenoma). Non-functioning adenomas may cause panhypopituitarism, headache, and bitemporal visual field defects when large.
Causes and risk
Most pituitary adenomas are sporadic. Multiple endocrine neoplasia type 1 (MEN1) and a few other genetic syndromes increase risk. They occur across all ages but peak in the 30 -- 60 age range.
How it is evaluated
Full anterior pituitary hormone panel (prolactin, IGF-1, ACTH, cortisol, LH, FSH, testosterone or estradiol, TSH, free T4) and a 24-hour urine cortisol or overnight dexamethasone suppression test are obtained. Pituitary MRI with gadolinium characterizes size, sellar extension, and proximity to the optic chiasm. Formal visual field testing is performed for tumors approaching or touching the chiasm.
Treatment
Prolactinomas are treated medically with dopamine agonists as first-line. Functioning adenomas causing acromegaly or Cushing's disease are primarily treated with transsphenoidal surgery. Non-functioning macroadenomas causing mass effect also typically require surgery. Radiotherapy is reserved for residual or recurrent tumor. Pituitary hormone deficiencies are replaced as needed.