Ectopic Suprasellar Thyrotropin-Secreting Pituitary Adenoma: Case Report and Literature Review

Abstract

Ectopic thyroid-stimulating hormone (TSH)-secreting pituitary adenomas are rare and can often be misdiagnosed as primary hyperthyroidism. We present a case of an ectopic suprasellar TSH-secreting pituitary adenoma. A literature review of previously reported ectopic TSH-secreting and suprasellar pituitary adenomas is included to illustrate the clinical characteristics of this disease entity and the diversity of operative approaches to treating ectopic suprasellar pituitary adenomas. A 46-year-old man presented with typical clinical signs of hyperthyroidism and a history of progressive visual field impairment and vision loss. Laboratory investigations revealed that the patient had elevated levels of free thyroxine and free triiodothyronine and a normal level of TSH. Neuro-ophthalmologic examination showed right eye/left eye= 1.0/0.6 and left temporal hemianopia. Magnetic resonance imaging revealed a mass located in the suprasellar space. The patient underwent preoperative short-term octreotide treatment followed by gross total resection of the tumor via the extended endoscopic endonasal transtuberculum sellar approach. At 6-month follow-up evaluation, the patient's endocrinologic function tests met the criteria for cure, and magnetic resonance imaging revealed a normal pituitary gland and stalk with no tumor recurrence. Histologic diagnosis confirmed the presence of a TSH-secreting pituitary adenoma. To the best of our knowledge, this is the first reported case of an ectopic suprasellar TSH-secreting pituitary adenoma. Preoperative preparation and complete resection are the keys to a cure. The extended endoscopic endonasal transtuberculum sellar approach is an alternative minimally invasive method for the removal of an ectopic suprasellar pituitary adenoma.