A patient with an ectopic sphenoid bone TSH secretory adenoma: Case report and review of the literature

Abstract

Ectopic thyroid-stimulating hormone (TSH)oma located outside the sella turcica is exceedingly rare and can be associated with significant diagnostic delay. The clinical presentation depends on the anatomical location and size of the ectopic tumor and the degree of thyrotoxicosis. A 71-year-old woman presented with goiter and thyrotoxicosis. Initial investigations revealed elevated free thyroxine (fT4) and tri-iodothyronine (fT3) with inappropriately high-normal TSH. Assay interference was unlikely, pituitary magnetic resonance imaging (MRI) scan was reported as “normal,” and germline sequencing was negative for thyroid hormone receptor ß pathogenic variants. One year later, total thyroidectomy for enlarging symptomatic goiter and suspicious nodule revealed multifocal microscopic papillary thyroid carcinoma. Six years later, she presented to an ear, nose, and throat surgeon with nasal congestion, and a sphenoid bone mass was discovered on nasoendoscopy and imaging. Ectopic TSHoma was confirmed on surgical resection, and a review of the initial pituitary MRI scan revealed the mass which had initially been missed. This is the first reported case of an ectopic TSHoma located in the sphenoid bone. Ectopic TSHoma should be considered in patients with inappropriate TSH secretion when more common differentials are excluded including thyroid hormone resistance or pituitary TSHoma.

Central hyperthyroidism due to an ectopic TSH-secreting pituitary tumor: a case report and literature review

“…Ectopic TSH-secreting tumors and TSH-secreting pituitary adenoma exhibit similar clinical manifestations of central hyperthyroidism, such as palpitation, weight loss, heat in tolerance, and thyroid goiter. In some cases, pituitary adenomas can cause hypopituitarism and associated symptoms, while ectopic tumors can present with ear, nose, and visual symptoms, among others ( 8 , 17 ). Among the previous reported cases of ectopic TSH-secreting tumors, 10 cases were found to be located in the nasopharynx ( Supplementary Table S1 ).…”

“…Therefore, ectopic TSH-secreting pituitary adenomas causing hyperthyroidism are even rare. Since the first reported case in 1996, only 15 cases have been documented in the literatures (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17). In some occasions, the differential diagnosis between TSHsecreting tumor and pituitary resistance to thyroid hormone action (PRTH) can be difficult, especially when the absence of a TSHsecreting tumor in the pituitary gland is recognized.…”