Trummer Christian, Reiher Hannes, Theiler-Schwetz Verena, Pandis Marlene, Gstettner Christian, Potzinger Peter, Keck Tilman, Pieber Thomas R, Lax Sigurd, Haybaeck Johannes, Stepan Vinzenz, Pilz Stefan
Division of Endocrinology and Diabetology, Department of Internal Medicine, Medical University of Graz, Graz, Austria.
Department of Internal Medicine, Krankenhaus der Elisabethinen, Graz, Austria.
Eur Thyroid J. 2020 Feb;9(2):106-112. doi: 10.1159/000505020. Epub 2020 Jan 21.
The main differential diagnoses of secondary hyperthyroidism include thyrotropin-secreting neuroendocrine pituitary tumors (TSH-PitNETs) and resistance to thyroid hormone. As a rare cause of secondary hyperthyroidism, ectopic thyrotropin-producing neuroendocrine pituitary tumors must also be considered.
A 48-year-old female patient with overt hyperthyroidism and elevated thyrotropin was admitted to the endocrine outpatient clinic of a secondary care hospital in March 2018. The patient had an inconspicuous pituitary MRI and F18-F-DOPA PET-CT, but showed a tumor mass located at the pharyngeal roof. Most biochemical tests and an increased tracer uptake of the pharyngeal mass in a Ga68-DOTANOC PET-CT argued for the presence of an ectopic TSH-PitNET. After treatment with octreotide over 5 days and a consecutive normalization of free thyroxine and free triiodothyronine, the tumor was endoscopically resected. Histologically, the mass consisted of small partially spindle, partially polygonal monomorphic to mildly pleomorphic cells with immunoreactivity for thyrotropin and luteinizing hormone. Postoperatively, the patient required intermittent levothyroxine therapy.
Ectopic TSH-PitNETs represent an extremely rare cause for secondary hyperthyroidism. While the diagnostic process may be complicated by negative imaging studies of the pituitary gland, family history, biochemical tests, and functional imaging using gallium-labelled somatostatin analogues may be helpful in establishing the diagnosis.
继发性甲状腺功能亢进的主要鉴别诊断包括促甲状腺激素分泌性神经内分泌垂体肿瘤（TSH-PitNETs）和甲状腺激素抵抗。作为继发性甲状腺功能亢进的罕见病因，异位促甲状腺激素分泌性神经内分泌垂体肿瘤也必须予以考虑。
一名48岁患有明显甲状腺功能亢进且促甲状腺激素升高的女性患者于2018年3月入住一家二级护理医院的内分泌门诊。该患者垂体MRI和F18-F-DOPA PET-CT检查结果不明显，但显示在咽顶部有一个肿瘤肿块。大多数生化检查以及Ga68-DOTANOC PET-CT检查显示咽部肿块的示踪剂摄取增加，提示存在异位TSH-PitNET。在使用奥曲肽治疗5天后，游离甲状腺素和游离三碘甲状腺原氨酸连续恢复正常，随后通过内镜切除肿瘤。组织学检查显示，肿块由部分呈梭形、部分呈多边形的小细胞组成，细胞形态单一至轻度多形性，对促甲状腺激素和促黄体生成素具有免疫反应性。术后，患者需要间歇性左甲状腺素治疗。
异位TSH-PitNETs是继发性甲状腺功能亢进极其罕见的病因。虽然垂体的阴性影像学检查可能会使诊断过程复杂化，但家族史、生化检查以及使用镓标记生长抑素类似物的功能成像可能有助于确诊。
