Prepubertal Graves' disease with hyperactivity and overgrowth since early childhood.

Although Graves' disease is a prevalent endocrine disorder, it is rare in prepubertal patients. Here, we describe the case of a middle childhood boy diagnosed with Graves' disease. The patient experienced exophthalmos, hyperactivity and overgrowth. Endocrinological tests revealed positivity for hyperthyroidism and thyrotropin receptor antibodies. Ultrasonography revealed an enlarged thyroid gland with increased blood flow. The onset of symptoms was estimated to have occurred around the age of 4 years based on the growth chart and past facial photographs. We speculate that it took more than 2 years from onset to diagnosis in this patient. The symptoms of Graves' disease in childhood, such as hyperactivity or overgrowth, may be overlooked as problems with developmental characteristics or growth effects. Although Graves' disease is rare in this age group, it should be considered in the differential diagnosis.