Objective: To report a rare case of a thyrotropin (TSH)-secreting pituitary adenoma associated with thyroid carcinoma.
Methods: We report the clinical history, imaging studies, and laboratory and pathologic data in a male patient affected by TSH-secreting pituitary adenoma and goiter; histologic evaluation revealed thyroid carcinoma.
Results: A 50-year-old man complained of years of palpitations, hypertensive crisis, and excessive nervousness that tended to progressively worsen. The basal and dynamic hematologic evaluation showed the presence of high free thyroid hormone levels with inappropriate levels of TSH. The thyroid morphologic study using Doppler ultrasonography showed a gland of increased volume with multiple nodular lesions bilaterally. The nuclear magnetic resonance of the pituitary gland described a microadenoma. A total thyroidectomy was performed followed by neurosurgical treatment of the pituitary lesion. The definitive thyroid histologic examination showed the presence of minimally invasive follicular carcinoma of 17 mm diameter. The patient firmly refused surgical removal of the pituitary adenoma. He was started on replacement therapy with thyroxine. Twelve months later, the hematologic examinations showed normal thyroid hormone levels and a TSH of 6.97 uIU/mL. The pituitary nuclear magnetic resonance showed a stable lesion without difference in size.
Conclusion: The clinical association between thyroid carcinoma and TSH-producing adenoma is rare, with the removal of the pituitary lesion being mandatory. Pituitary surgery, in this case, is impossible, showing that TSH-producing microadenoma could seldom have an indolent behavior.