Responses to TRH, T3 suppression tests and histological findings by needle biopsy in patients with simple goitre in Japan.

Studies were performed in 120 patients with simple goitre, defined as relatively soft diffuse goitre. All were clinically and biochemically euthyroid and their antithyroid antibodies were negative. The TRH test was performed in 99 after the TRH test, while satisfactory biopsies of the thyroid were obtained in 37. The results showed that 28 of the 115 cases (24%) had an abnormal response to TRH; 8 (7%) were hyporesponders and 20 (17%) were hyperresponders. The T3 suppression test showed that 3 of 99 cases (3%) were non-suppressible. As determined by histological examination of the needle biopsy specimen, 17 of the 37 cases (46%) had normal follicles without lymphocytic infiltration, 10 (27%) had diffuse chronic thyroiditis, 5 (14%) had focal thyroiditis and 4 (11%) had diffuse epithelial hyperplastic change, and 1 (3%) had an adenomatous goitre. It is suggested that simple goitre defined as above includes various thyroid diseases and that the results of TRH tests, antithyroid antibody estimations and histological findings do not correlate in many patients.