PITUITARY NEOPLASMS

Almost always benign

< 1cm in diameter = "Microadenomas"

I. Prolactin-secreting tumors (60% of functioning pituitary tumors)

  1. Clinical features
    1. Galactorrhea (only in about 1/3)
    2. Headache
    3. Diplopia or hemianopsia
    4. Amenorrhea & infertility
    5. In men can cause Erectile Dysfunction, decreased libido, and infertility
  1. Initial evaluation--Coned-down lateral XR of sella turcica is sufficient if PRL is < 100ng/ml and no visual change or HA; otherwise, MRI
  1. Treatment
  1. Dopamine agonists (80-90% of microadenomas and 60-75% of macroadenomas will respond)
  1. Bromocriptine
  2. Cabergoline (see Med. Lett. 39:58, 1997)
  1. Long-acting Depot dopamine agonists
  2. Surgery
  3. Somatostatin-receptor-subtype-selective analogs
  4. If no HA or vis. sx, can just check yearly PRL levels & visual field and MRI q2-3y

II. Growth-Hormone secreting tumors (20% of functional pituitary tumors)

  1. Clinical features
    1. Acromegaly (us. only after 10y or so)
    2. Headaches
    3. Hypopituitarism
    4. Diplopia or hemianopsia
  1. Treatment
    1. Surgery is generally tx of choice
    2. Somatostatin analogs (e.g. octreotide), sometimes in combination w/bromocriptine
    3. Somatostatin-receptor-subtype-selective analogs
    4. GHRH antagonists
    5. Irradiation

III. ACTH-secreting tumors (15% of functional pituitary tumors)

  1. Treatment
    1. Surgery generally tx of choice but may result in hypocortisolism
    2. Irradiation + Cortisol-decreasing drugs (e.g. mitotane, ketaconazole, aminoglutethimide, and metapyrone)

IV. TSH-secreting tumors--RARE

  1. Treatment
    1. Surgery + irradiation are generally tx of choice
    2. Somatostatin analogs, e.g. octreotide

V. Nonfunctioning tumors (1/3 of all pituitary tumors; the most common macroadenomas)

  1. Clinical presentation
    1. Headache
    2. Diplopia or hemianopsia
    3. Hypopituitarism
    4. Hypogonadism, occasionally
  1. Treatment
    1. Surgery is generally tx of choice
    2. Irradiation
    3. GRH antagonists

(Source: summary of Ann. Int. Med. 129:472, 1998--AFP)