What Causes Palpable Goiter In Neck And Delayed Relaxation Phase?

A well-proportioned woman, 1.62 m in height, 62.7 kg in weight, and with sparse eyebrows (particularly at the lateral margins). Her facial features appeared slightly puffy in comparison to the photograph on her driver’s license taken 3 years before.
The pulse rate was 56 bpm and the blood pressure 139/87 mm Hg.
Examination of her neck disclosed a small palpable goiter.
Her deep tendon reflexes were normally contractive but showed a delayed relaxation phase. What may be the problem?