Endocrine Abstracts

Introduction: The goiter represents the most common of all the disorders of the thyroid gland. Many Factors may be involved in the evolution of multinodular goiter. Although thyroid stimulating hormone (TSH) was described as the most important goitrogen factor, impairment of TRH-induced TSH release was reported with nodular goiter, suggesting thyroid autonomy. Herein, we report two cases of an isolated thyrotropin deficiency in patient presented with a voluminous goiter.

Observation 1: A 80-year-old man with no past medical history presented with a 6-year history of a massive multinodular goiter and inspiratory dyspnea. Physical examination showed no signs of dysthyroidism. A computed tomography (CT) scan revealed heterogeneous enhancing of an enlarged thyroid gland (10*13*12 cm) with extension into the chest and compression of the trachea and esophagus. Hormonal tests revealed an isolated central hypothyroidism with a suppressed FT4 levels of 0.69 ng/dl and 0.61 ng/dl (reference range: 0.7–1.5 ng/dl) and a normal TSH levels of 0.55 mIU/l (reference range: 0.35–4.95 mIU/l). Patient was put on Levothyroxine replacement therapy and then underwent total thyroidectomy.

Observation 2: A 38-year-old man with no past medical history was admitted to our department with a massive goiter without compressive signs. Cervical computed tomography (CT) scan revealed a multinodular goiter with chest extension. Thyroid function tests showed a low serum FT4 level of 0.45 ng/dl and a normal serum TSH level of 0.52 mIU/l controlled to many times with no other hormonal deficiency detected.

Conclusion: Among too many factors involved in the development of multinodular goiter, TSH remains the most important one. However, in our cases, the multinodular goiter was associated with a central hypothyroidism which is not a common condition.