Endocrine Abstracts

Pituitary hyperplasia is a relatively common condition that occurs in both physiological and pathological states. Pregnancy is the most common condition associated with physiological pituitary enlargement, associated primarily with lactotroph hyperplasia. Pathological hyperplasia has been shown to be associated with end organ insufficiency from primary gonadal insufficiency, primary adrenal insufficiency, and primary hypothyroidism. We present the case of a 33-year-old male with profound primary hypothyroidism following treatment of Graves’ disease with Carbimazole treatment and secondary pituitary hyperplasia that resolved after thyroid hormone supplementation (175 mcg/day) in addition to Carbimazole (40 mg daily) treatment. Our patient is a 33-year-old Caucasian male presented with symptoms of hyperthyroidism due to Graves’ disease and he was treated with carbimazole. A few months later he presented with symptoms of severe headache, lack of energy, exhausted and symptoms of low libido and sex drive. Repeat Thyroid function test, revealed a thyroid stimulating hormone (TSH) >150 mU/l (NR, 0.35-5.5) FT4 4 (NR, 9-23 pmol/l), free T3, 2.2 (NR 3.5-6.5 pmol/l), Thyroid stimulating inhibiting immunoglobulin (TBII) 5 IU/l, cortisol 334 nmol, serum testosterone 1.7 nmol/l , LH 1.3 IU/l, FSH 1.5 IU/l, and serum prolactin 546 (45-375 mIU/l). MRI of the pituitary revealed an enlarged pituitary gland with suprasellar extension without optic nerve involvement. Repeat MRI Scan of the pituitary gland a few months later revealed normal structure of pituitary gland.

Conclusion: Pituitary hyperplasia in primary hypothyroidism is not uncommon and close follow up of patient with hyperthyroidism is very important to avoid patient from developing a severe hypothyroidism while in medical treatment.