Challenging diagnosis of resistance to thyroid hormone in a patient with pituitary adenoma

Resistance to Thyroid Hormone Beta Due to THRB Mutation in a Patient Misdiagnosed With TSH-Secreting Pituitary Adenoma

Elevated concentrations of T3 and T4 concomitant with nonsuppressed TSH are found in both TSH-producing tumors and resistance to thyroid hormone beta (RTHβ), posing a diagnostic challenge. We demonstrate here a 54-year-old female who presented with palpitations, goiter, and elevated free T4 with nonsuppressed TSH concentrations (TSH 2.2 mIU/L [normal range, NR 0.27-4.2 mIU/L] and FT4 59.08 pmol/L [NR 12.0-22.0 pmol/L]). Because magnetic resonance imaging revealed a pituitary microadenoma (4 mm), she was diagnosed with TSH-secreting pituitary adenoma and underwent transsphenoidal surgery. Pathological reports showed no tumor cells. Subsequent genetic testing revealed a pathogenic variant in the THRB gene resulting in a His435Arg amino acid substitution in the T3 receptor isoform beta 1 (TRβ1), suggestive of RTHβ. In vitro and ex vivo studies revealed that the His435Arg mutated TRβ1 (TRβ1-H435R) completely abolishes the T3-induced transcriptional activation, nuclear receptor corepressor 1 release, steroid receptor coactivator 1 recruitment, and T3-induced thyroid hormone target gene expression, confirming the pathogenicity of this variant. The identification of a pituitary microadenoma in a patient with RTHβ led to a misdiagnosis of a TSH-producing tumor and unnecessary surgery. Genetic testing proved pivotal for an accurate diagnosis, suggesting earlier consideration in similar clinical scenarios.

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

Ectopic thyroid-stimulating hormone (TSH)-secreting tumors are extremely rare, with only 15 reported cases in the literature. Herein, we described a 60-year-old female patient with thyrotoxicosis and elevated or unsuppressed levels of TSH. Family history and laboratory and genetic tests did not support a diagnosis of resistance to thyroid hormone (RTH). Given the unsuppressed TSH, TSH-secreting tumor was suspected, and magnetic resonance imaging (MRI) of the pituitary gland was performed. Surprisingly, the MRI scans revealed a nodule in the nasopharynx rather than a pituitary tumor in the sella region. Further evaluation using Gallium-68 DOTATATE positron emission tomography/computed tomography (68Ga-DOTATATE PET/CT) demonstrated increased DOTATATE uptake in the nasopharyngeal nodule. Additionally, an octreotide suppression test (OST) revealed an obvious reduction in TSH levels, further supporting the suspicion of the nasopharyngeal mass as the cause of inappropriate TSH secretion. To prepare for surgery, the patient received preoperative administration of octreotide, resulting in the normalization of TSH and thyroid hormone levels. The patient subsequently underwent successful surgical removal of the nasopharyngeal mass. Following the procedure, the patient experienced complete resolution of hyperthyroidism symptoms, with TSH declined and thyroid hormone levels returned to normal. Histochemistry analysis of the tumor revealed positive staining for TSH, growth hormone (GH), prolactin (PRL), luteinizing hormone (LH), and somatostatin receptor 2 (SSTR2). We discussed differential diagnosis of hyperthyroidism due to inappropriate TSH secretion, with a particular emphasis on the importance of 68Ga-DOTATATE PET/CT in combination with OST for identifying ectopic pituitary tumors.

The clinical characteristics and gene mutations associated with thyroid hormone resistance syndrome coexisting with pituitary tumors

AIMS

Resistance to thyroid hormone (RTH) and pituitary tumors are both rare diseases, and the differential diagnosis of these two diseases is difficult in some cases. There are also patients who have both conditions, making diagnosis more difficult. To better understand this aspect, we analyzed the clinical characteristics and gene mutations of RTH coexisting with pituitary tumors.

METHODS

Database retrieval was conducted in the PubMed, Cochrane Library, and SinoMed databases, and the search contents were case reports or case series of patients with RTH coexisting with pituitary tumors. The demographic, clinical manifestations, and imaging characteristics of pituitary tumors and gene mutations were summarized.

RESULTS

Thirteen articles involving 16 patients with RTH coexistent with pituitary tumors, consisting of 13 female patients, one male patient, and two patients with unknown sex, were included. The patients were 10 to 79 years old and most patients were 41-55 years old (43.75%). The 16 patients were from seven different countries and three continents (Asia, the Americas, and Europe). All the patients showed an abnormal secretion of TSH, and five patients underwent transsphenoidal surgery. Finally, four patients were pathologically confirmed to have TSHoma. A total of 11 different mutations occurred at nine amino acid sequence sites (251, 310, 344, 347, 383, 429, 435, 438, and 453). Two different mutations occurred in both the no. 435 and no. 453 amino acid sequences. Fourteen patients provided their treatment histories, and all had undergone different treatment regimens.

CONCLUSIONS

Patients with both RTH and pituitary tumors had multiple clinical manifestations and different thyroid functions, imaging characteristics of pituitary tumors, genetic mutations of THRβ, and treatments. However, due to the limited number of cases, the patients were mainly women. Further studies with more cases that focus on the mechanism are still needed.

Resistance to Thyroid Hormones: A Case-Series Study

The aim of the study is to describe the clinical features of two unrelated patients with resistance to thyroid hormones (RTH), the first, a total thyroidectomized patient, and the second, a pregnant woman. We report the features found in her newborn who also showed RTH. Patient 1 is a 38-year-old man with total thyroidectomy managed for excessive thyroid stimulating hormone (TSH) production, which poorly responded to the replacement therapy. He was found with a THRβ c.1378G>A p.(Glu460Lys) heterozygous mutation, which was also present in other members of his family (son, brother, and father). Interestingly, Patient 1 had hypertension, dyslipidemia, and hepatic steatosis, which have been recently suggested as RTH-related comorbidities. Patient 2 is a 32-year-old pregnant woman with multinodular goiter, and the THRβ heterozygous variant c.959G>C, that, to the best of our knowledge, has been reported in literature only once. Her newborn had tachycardia and increased thyroid hormone levels, and showed the same mutation. After delivery, high parathyroid hormone (PTH) and calcium serum levels were found in Patient 2 and the scintigraphy showed the presence of adenoma of a parathyroid gland. This case-series study provides a practical example of the management of RTH in a thyroidectomized patient, a pregnant woman, and a newborn. A novel RTH pathogenic mutation is described for the second time in literature. Furthermore, the importance of metabolic assessment in patients with RTHβ has been highlighted and the possible correlation between RTH and primary hyperparathyroidism is discussed.

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

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.