Clinical presentation: A 36-year-old woman was referred for evaluation of a low TSH-level. She has been treated for hypothyroidism for 6 years when she was referred for evaluation of a nodular goiter which proved to be a false diagnosis.

Palpation: The right lobe was firm.

Laboratory tests: TSH 0.33 mIU/L. The aTPO level was above 1000 U/mL six years ago.

Ultrasound. The thyroid was moderately hypoechogenic and presented numerous discrete lesions. None of the latter corresponded to nodule in pathological sense. The right lobe was significantly larger compared with the left one. The difference in volume was not the usual 30-50% but more than 500%. The dimensions of the thyroid had not changed since the first visit.

Suggestion: To continue with daily 100 microgram levothyroxine. We suggested to maintain the TSH level between 0.2 and 2.5 mIU/L because of the enlargement of the right lobe.