Tumors of all kinds, cancerous & non cancerous are the result of Iodine deficiency.
Iodine supplements have also cured cancerous & non cancerous tumors.
There is a lot to Iodine supplementation. Dr. Brownstein recommends taking Lugols or Iodoral Iodine with the required co-supplements. In cases of tumors, he recommends slowly titrating up to 300mg daily.
Related to the pituitary:
"The vitamin A and iodine both play a role in pituitary function. One of the major roles of the pituitary is control over your thyroid gland, a hormone gland located in your throat. Your pituitary releases the hormone thyroid stimulating hormone, or TSH, to stimulate thyroid activity, which boosts your metabolism. Vitamin A affects your pituitary's ability to control thyroid gland activity, notes a study published in the "International Journal for Vitamin and Nutrition Research" in 2007. Iodine also helps your thyroid gland respond properly to signals sent from the pituitary gland. Low levels of vitamin A and iodine both negatively affect communication between your pituitary and thyroid glands, disrupting normal pituitary function, explains the 2007 study."