Adénomes hypophysaires à TSH ou adénomes thyréotropes

Simultaneous Coexistence of Thyrotropin-Prolactin-Secreting Adenoma and Papillary Thyroid Carcinoma

Background

The thyrotropin-secreting adenomas are very rare and even more rare when they simultaneously coexist with thyroid carcinoma. So far, only sixteen cases have been reported in the literature. Here, we present a unique case of successful management of a concurrent case of thyrotropin-prolactinoma with papillary thyroid carcinoma. Case Presentation. A 50-year-old Moroccan woman underwent a total thyroidectomy and complementary totalization by iratherapy for papillary thyroid carcinoma, who presented persistence of an inappropriate secretion of the thyroid-stimulating hormone (TSH > 4 mUI/L) despite of levothyroxine suppressive therapy (300 μg/d). After eliminating noncompliance, interfering medicines, and thyroid malabsorption, a pituitary adenoma (12 mm) was documented at magnetic resonance imaging. The patient has had transsphenoidal pituitary adenomectomy with histology confirming a thyrotropin-prolactin-secreting adenoma. After surgery and lanreotide treatment failures, we noted a complete response (TSH < 0.5) with cabergoline treatment (3 mg/week).

Conclusion

The unusual association of thyroid adenocarcinoma and TSHoma enriches the hypothesis of a potential link between thyrotropic hypersecretion and thyroid carcinogenesis. Our case also illustrates the difficulty of monitoring thyroid carcinoma in nonremission of a TSHoma.

Syndrome of Reduced Sensitivity to Thyroid Hormones: Two Case Reports and a Literature Review

Resistance to thyroid hormone (RTH) is an extremely rare dominantly inherited condition of impaired tissue responsiveness to thyroid hormone (TH). Most patients with RTH have mutations in the gene that encodes the β isoform of the receptor of thyroid hormone (THR-β gene). Mutant receptors are unable to activate or repress target genes. The majority of them are asymptomatic or rarely have hypo- or hyperthyroidism. RTH is suspected by the finding of persistent elevation of serum levels of free T3 (FT3) and free T4 (FT4) and nonsuppressed TSH. We present two cases of RTH diagnosed after total thyroidectomy. The first patient was initially diagnosed with primary hyperthyroidism due to toxic multinodular goiter. The second patient had undergone thyroidectomy for multinodular goiter 16 years before diagnosis of RTH. After thyroidectomy, although on relatively high doses of levothyroxine, both of them presented with the laboratory findings of RTH. Genetic analysis revealed RTH.

[Manifestations and prognosis of thyrotropin-secreting pituitary adenomas: a case series of three patients]

INTRODUCTION

Among pituitary adenomas, thyrotropinomas were previously considered as extremely rare and resistant to therapy. However, the common use of the sensitive TSH measurement and the improvement of pituitary imaging have modified their clinical and hormonal presentation.

CASE REPORTS

We here report three cases of TSH secreting pituitary adenoma that highlight the great diversity of the clinical, hormonal and morphological presentation, and their better prognosis. In the presence of an inappropriate TSH secretion, the main differential diagnosis is the syndrome of thyroid hormone resistance. The role of somatostatin analogue prior to the surgical treatment of TSH secreting pituitary adenoma is also underlined in this report.

CONCLUSION

The increasing frequency and early diagnosis of TSH secreting pituitary adenoma may be explained by ultrasensitive methods now used for TSH measurement and progress in pituitary imaging, mainly with MRI. This changing spectrum in the presentation and the excellent response to somatostatin analogues improved in the prognosis of the disease.