TSH adenoma and syndrome of resistance to thyroid hormones—Two cases report of syndrome of inappropriate secretion of thyrotropin

Abstract

SITSH (syndrome of inappropriate secretion of thyrotropin) is a rare clinical state defined as uninhibited serum thyroid stimulating hormone in the presence of elevated thyroid hormone. This state is complicated and mainly caused by the abnormal feedback of hypothalamus–pituitary thyroid axis. The TSH adenoma (TSH‐oma) and resistance to thyroid hormones (RTH) are the main etiologies of SITSH. As is well known that the treatment strategies of RTH and TSH‐oma are apparently different, thus identifying the difference between RTH and TSH‐oma is of great significance for the diagnosis and treatment of SITSH. Case description A 62‐year‐old man with a state of elevated thyroid hormones and inappropriate elevated serum TSH level was hospitalized in 2016. Results of the pituitary enhanced magnetic resonance imaging and the somatostatin test respectively demonstrated a space‐occupying lesion of pituitary and an elevated serum sex hormone binding globulin (SHBG) and inhibited TSH secretion, which indicated the occurrence of TSH‐oma. In 2019, a 23‐year‐old girl with a state of elevated thyroid hormones and inappropriate normal serum TSH was hospitalized. Interestingly, whole exome sequencing detection suggested a pathogenic mutation in thyroid hormone receptor β (THRB) gene, which has been shown to be associated with RTH. Conclusions The difference between TSH‐oma and RTH ought to be clarified for their accurate diagnose and treatment. The clinical experiences of the two cases reported here suggest that more detail information such as family medical history, serum SHBG level, and THRB gene test is helpful for the diagnose and treatment of TSH‐oma and RTH. Additionally, we also summarized the identification points, diagnosis process, and treatment strategies for these two rare diseases.

Resistance to Thyroid Hormones: A Case-Series Study

“…To distinguish between RTH and TSH-producing pituitary tumors may be challenging as THs and TSH concentrations are not different. On the other hand, pituitary imaging can help in the differential diagnosis [ 27 ]. Interestingly, while Patient 2 exhibited normal or marginally increased FT4 levels, her newborn showed a significant increase in FT4 levels.…”

Syndrome of inappropriate secretion of thyroid-stimulating hormone in a subject with galactorrhea and menstrual disorder and undergoing infertility treatment

“…In addition, PRL and/or GH secretion is also enhanced in some subjects with TSHoma. [1][2][3][4][5][6] Since TSH-producing thyrotrophs, PRL-secreting lactrophs, and GH-producing somatotrophs are all derived from Pitproducing cells, we assume that such commonality of their origins is associated with the increased secretion of PRL and/or GH in some subjects with TSHoma. In this subject, PRL showed a normal upper limit, which might have, at least in part, facilitated the disturbance of fertility.…”

“…In addition, some cases of SITSH can have galactorrhea or menstrual disorder due to increased levels of prolactin (PRL) and/or decreased levels of luteinizing hormone (LH) or follicle stimulating hormone (FSH), as well as increased levels of TSH. [1][2][3][4][5][6] When we fail to recognize the presence of SITSH, thyroid ablation may be needed to further expand the pituitary tumor volume. The first therapeutic approach to SITSH is pituitary neurosurgery.…”

Neonatal Outcomes of Pregnancies Complicated by Maternal Hyperthyroidism

“…6 Other etiologies of hyperthyroidism in pregnancy are toxic adenoma, toxic nodular goiter, thyroiditis, gestational hyperthyroidism and mutations in the TSH receptor. 7 The causative antibodies in GD are thyroid-stimulating hormone receptor antibodies (TRAb) that belong to the immunoglobulin G class. TRAbs cross the placenta freely, particularly during the second half of pregnancy.…”

“…6 Other etiologies of hyperthyroidism in pregnancy are toxic adenoma, toxic nodular goiter, thyroiditis, gestational hyperthyroidism and mutations in the TSH receptor. 7 …”