Ansari Mohd Saleem, Almalki Mussa H
Obesity, Endocrine and Metabolism Center, King Fahad Medical City , Riyadh , Saudi Arabia.
Obesity, Endocrine and Metabolism Center, King Fahad Medical City, Riyadh, Saudi Arabia; College of Medicine, King Fahad Medical City, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia.
Front Endocrinol (Lausanne). 2016 Apr 26;7:35. doi: 10.3389/fendo.2016.00035. eCollection 2016.
Secondary pituitary enlargement due to primary hypothyroidism is not a common manifestation. The loss of thyroxin feedback inhibition in primary hypothyroidism causes overproduction of thyrotropin-releasing-hormone (TRH), which results in secondary pituitary enlargement. TRH has a weak stimulatory effect on the lactotroph cells of the pituitary, so a mild to moderate increase in prolactin (PRL) levels is expected. We report the case of a 67-year-old female who presented with a large pituitary mass and a very high level of TSH in association with a significant rise in PRL level. In this case, diagnosing a sellar mass was challenging; it was difficult to distinguish between pituitary prolactinoma and primary hypothyroidism with secondary pituitary hyperplasia. Thyroid hormone replacement proved that this patient's hyperprolactinemia was due to hyperplasia of the pituitary gland. As such, making the correct diagnosis and initiating thyroid hormone therapy can prevent unnecessary treatment with dopamine agonists.
原发性甲状腺功能减退导致的继发性垂体增大并非常见表现。原发性甲状腺功能减退时甲状腺素反馈抑制作用丧失，导致促甲状腺激素释放激素（TRH）分泌过多，进而引起继发性垂体增大。TRH对垂体的催乳素细胞有微弱的刺激作用，因此预计催乳素（PRL）水平会轻度至中度升高。我们报告一例67岁女性病例，该患者出现巨大垂体肿块，促甲状腺激素（TSH）水平极高，同时PRL水平显著升高。在该病例中，诊断鞍区肿块颇具挑战性；难以区分垂体催乳素瘤与原发性甲状腺功能减退伴继发性垂体增生。甲状腺激素替代治疗证明该患者的高催乳素血症是由垂体增生所致。因此，做出正确诊断并启动甲状腺激素治疗可避免不必要的多巴胺激动剂治疗。
