下垂体性TSH分泌亢進症

Thyroid hemiagenesis (THA) is a relatively rare disorder in which one thyroid lobe fails to develop. Although most individuals remain clinically euthyroid, they typically exhibit higher thyrotropin (TSH) concentrations than those with a bilobed thyroid gland, possibly reflecting reduced thyroidal reserve and a chronic compensatory response by pituitary thyrotrophs. While pituitary hyperplasia has been reported in the setting of hypothyroidism in THA, a TSH-secreting pituitary neuroendocrine tumor (thyrotropinoma) has not previously been described in this condition. A 30-year-old woman underwent thyroid function testing during the first trimester of her first pregnancy, which revealed a TSH concentration of 2.57 mIU/L. In accordance with local clinical practice, thyroid ultrasonography was performed and demonstrated absence of the left thyroid lobe, consistent with THA. Given the TSH level >2.5 mIU/L and the potentially limited thyroidal functional reserve associated with THA, subclinical hypothyroidism was diagnosed. To prevent the development of overt hypothyroidism during pregnancy and its associated maternal and fetal complications, levothyroxine therapy was initiated. Over the following years, levothyroxine was progressively uptitrated, but despite development of clinical features of thyrotoxicosis, with raised free thyroid hormone levels, serum TSH remained unsuppressed, prompting evaluation for this discordant thyroid function pattern. Pituitary MRI demonstrated an 11mm macroadenoma. Further investigations revealed an elevated alpha-glycoprotein subunit (α-GSU) level and an attenuated TSH response to TRH stimulation. A trial of a depot somatostatin receptor ligand resulted in a marked reduction in thyroid hormone levels. Together, these findings supported the diagnosis of a thyrotropinoma. Transsphenoidal surgery was performed, and histology confirmed a PIT1 lineage plurihormonal tumor with predominant TSH expression. Following surgery, the patient developed central hypothyroidism and was recommenced on levothyroxine therapy. We report the first documented case of a pituitary adenoma in a patient with THA; notably, the lesion was the rarest pituitary tumor subtype, a thyrotropinoma. This observation raises the possibility of a biological link driven by chronic thyrotroph stimulation, potentially contributing to adenoma formation. A similar feedback-driven mechanism has been proposed to explain cases of coexistence of resistance to thyroid hormone β (RTHβ) and thyrotropinoma. Therefore, in patients with THA receiving levothyroxine therapy, the development of hyperthyroxinaemia with a non-suppressed TSH should prompt consideration of a thyrotropinoma.

OBJECTIVE: Thyroid-stimulating hormone (TSH)-secreting pituitary neuroendocrine tumors (TSH-PitNET) are extremely rare during pregnancy, with limited understanding of their impact. CASE REPORT: A primiparous woman in her mid-20s was diagnosed with TSH-PitNET during pregnancy following symptoms, including hyperemesis gravidarum and mild palpitation. At 12 weeks of gestation, a blood test revealed that TSH was not suppressed despite elevated thyroid hormone levels, consistent with SITSH (syndrome of inappropriate TSH secretion). No thyroid hormone receptor β (TRβ) mutation was detected. MRI revealed a pituitary macroadenoma, and TSH-PitNET was diagnosed. Monthly lanreotide injections were administered from 18 weeks until term. At 40 weeks, she underwent an emergency cesarean delivery due to severe headache and mild hypertension, delivering a healthy infant. Transsphenoidal macroadenoma resection was performed three months postpartum. CONCLUSION: This case highlights that a conservative approach with lanreotide and close monitoring can achieve favorable outcomes for both mother and child in TSH-PitNET during pregnancy.

Collision tumors in the sellar region are uncommon, most frequently composed of pituitary adenomas and Rathke's cleft cysts. However, the coexistence of a craniopharyngioma and a pituitary adenoma represents an exceedingly rare entity. Here, we report a unique case of a 60-year-old woman presenting with progressive bilateral visual decline. Neuroimaging identified distinct sellar and suprasellar masses. The patient underwent endoscopic endonasal surgery with gross total resection (GTR). Postoperative histopathological analysis confirmed a collision tumor consisting of a papillary craniopharyngioma and a thyrotropin (TSH)-secreting pituitary adenoma. To the best of our knowledge, this is the first documented case of coexisting papillary craniopharyngioma and TSH-secreting pituitary adenoma in the sellar region.

BACKGROUND: Thyroid-stimulating hormone (TSH)-secreting pituitary adenoma (TSHoma) is a rare functional pituitary tumor that secretes TSH independently, thus stimulating the synthesis and secretion of thyroid hormone. Its clinical manifestation is central hyperthyroidism, and it is easily misdiagnosed as Graves' disease. At present, the treatment of TSHoma includes surgery, medication, and radiotherapy, and transsphenoidal pituitary surgery remains the first-line treatment. CASE PRESENTATION: This case involved a 61-year-old Chinese male with clinical manifestations of weight loss, heart palpitations, and shortness of breath, both thyroid hormone and TSH are elevated. The patient was diagnosed with a TSH/growth hormone (GH) co-secreting pituitary adenoma by serological examination, magnetic resonance imaging of the pituitary gland, and related functional tests. Due to thrombocytopenia and heart disease, the patient was deemed a poor candidate for immediate surgery and was therefore treated with octreotide. Thyroid function tests normalized after medication, and the diagnosis of TSHoma was verified. CONCLUSION: Although TSHoma is rare, it is not difficult to diagnose based on clinical presentation, ancillary examination, and functional testing. Thyroid hormone resistance syndrome is very similar to it and is therefore easily misdiagnosed. Early diagnosis and appropriate treatment can effectively control the disease and even achieve a clinical cure.

Concurrent thyrotropin (TSH) secreting and growth hormone (GH) secreting pituitary adenomas are rare entities. Although tumors of the PIT-1 lineage may coexpress TSH and GH, concurrent biologically active secretion resulting in central hyperthyroidism and acromegaly is uncommon. We report the case of a 42-year-old woman presenting with weight loss, palpitations, amenorrhea, and progressive acromegalic features. Biochemical evaluation revealed central hyperthyroidism with elevated free T4 and inappropriately normal TSH, markedly elevated insulin-like growth factor 1 (IGF-1) and GH, hyperprolactinemia, and elevated α-subunit. Pituitary magnetic resonance imaging demonstrated a 2.7-cm macroadenoma with cavernous sinus extension. She underwent transsphenoidal resection without complications. Pathology confirmed a mature plurihormonal PIT-1 lineage adenoma immunopositive for TSH, GH, and prolactin with a Ki-67 of 3%. Immediately postoperatively, thyrotoxicosis and hyperprolactinemia resolved, IGF-1 levels declined, acromegalic features improved, and menses resumed. Over the ensuing months, thyroid and prolactin tests remained within normal range, but the IGF-1 level remained elevated. This case illustrates the rare presentation of a PIT-1 lineage adenoma secreting biologically active TSH, GH, and prolactin. Comprehensive hormonal evaluation and long-term biochemical and radiologic surveillance are essential, given the risk of incomplete remission despite apparent surgical cure.