• Hideaki Kaneto, Shinji Kamei, Fuminori Tatsumi, Masashi Shimoda, Tomohiko Kimura, Atsushi Obata, Takatoshi Anno, Shuhei Nakanishi, Kohei Kaku, and Tomoatsu Mune.
• Department of Diabetes, Endocrinology and Metabolism, Kawasaki Medical School, Japan.
• Medicine (Baltimore). 2021 Dec 30; 100 (52): e28414e28414.

RationaleSyndrome of inappropriate secretion of thyroid-stimulating hormone (SITSH) is a rare cause of hyperthyroidism. Thyroid-stimulating hormone (TSH) levels are usually normal or high, and triiodothyronine (FT3) and free thyroxine (FT4) levels are usually high in subjects with SITSH.Patient ConcernA 37-year-old woman had experienced galactorrhea and menstrual disorder for a couple of years before. She had undergone infertility treatment in 1 year before, hyperthyroidism was detected and she was referred to our institution.DiagnosisShe was suspected of having SITSH and was hospitalized at our institution for further examination. The data on admission were as follows: FT3, 4.62 pg/mL; FT4, 1.86 ng/dL; TSH, 2.55 μIU/mL. Although both FT3 and FT4 levels were high, TSH levels were not suppressed, which is compatible with SITSH. In addition, in brain contrast-enhanced magnetic resonance imaging, nodular lesions were observed in the pituitary gland with a diameter of approximately 10 mm. In the thyrotropin-releasing hormone load test, TSH did not increase at all, which was also compatible with TSH-secreting pituitary adenoma. In the octreotide load test, the TSH levels were suppressed. Based on these findings, we diagnosed this subject as SITSH.InterventionsHardy surgery was performed after the final diagnosis. In TSH staining of the resected pituitary adenoma, many TSH-producing cells were observed. These findings further confirmed the diagnosis of pituitary adenoma producing TSH.OutcomesApproximately 2 months after the operation, TSH, FT3, and FT4 levels were normalized. Approximately 3 months after the operation, she became pregnant without any difficulty.LessonsWe should consider the possibility of SITSH in subjects with galactorrhea, menstrual disorders, or infertility. In addition, we should recognize that it is very important to repeatedly examine thyroid function in subjects with galactorrhea, menstrual disorder, or infertility.Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.

37 keywords...

hide…