Primary hypothyroidism with pituitary hyperplasia characterized by hypogonadotropic hypogonadism: a case report and review of the literature

Primary hypothyroidism with pituitary hyperplasia is a rare entity. It is characterized by hypogonadotropic hypogonadism and growth hormone (GH) deficiency. Despite advances in imaging, it is still not possible to clearly distinguish pituitary hyperplasia from pituitary tumors. We describe a case of primary hypothyroidism associated with pituitary hyperplasia. We reviewed 18 case reports of children or adolescents with short stature or hypogonadotropic hypogonadism from 2001 to 2019. In the present report, we studied a 15-year-old adolescent male whose first diagnosis was low gonadotropin development and growth retardation. Imaging examination revealed nodular signals in the saddle area of the pituitary gland, and endocrine function tests showed primary hypothyroidism. Levothyroxine tablets were taken as replacement therapy. A literature search found that 17 studies reported delayed bone age and growth retardation, but only 6 studies measured GH; 5 studies showed a decrease in GH. To distinguish primary hypothyroidism with subsequent pituitary hyperplasia from pituitary tumors, the definitive diagnosis should be based on clinical symptoms, endocrine examination, and prognosis following medication. For patients with hypothyroidism, thyroid hormone replacement therapy can result in a satisfactory prognosis, as well as improvements in clinical symptoms and serologic values. The pituitary function of those with pituitary hyperplasia can be slowly restored after negative feedback inhibition is rebalanced. However, patients with pituitary tumors should undergo surgery.