EUTHYROID GRAVES-DISEASE SHOWING NO THYROID ABNORMALITIES EXCEPT POSITIVE THYROID-STIMULATING ANTIBODY (TSAB) - 2 CASE-REPORTS

We report two cases of euthyroid Graves' disease in women who had opht halmopathy without previous history of hyperthyroidism. Enlargement of extraocular muscles was observed by magnetic resonance imaging (MRI). The patients had no thyroid enlargement and their serum concentration s of free T-4, free T-3, and TSH were normal. The sera were negative f or antithyroid microsomal and thyrogobulin antibodies, and anti-TSH re ceptor antibodies measured by radioreceptor assay. T-3 suppression tes t results were normal. Only thyroid-stimulating antibody (TSAb) measur ed by sensitive bioassay was positive. These findings indicate that se nsitive TSAb is the most useful laboratory test in the diagnosis of eu thyroid Graves' disease.