AUTONOMOUS THYROID ADENOMA - USEFULNESS O F THALLIUM SCINTIGRAPHY ANDHISTOLOGY

Clinical, biological, scintigraphic (99mTc, 1231, 201Tl) and histologi cal data were reviewed in 90 patients operated for autonomous adenomas (hot nodules). Analysis of the data gave the following results : 74,4 % of the nodules were solitary and 25.6 % occurred in a multinodular goiter (MNG). Hyperthyroidism (FT3-, FT4-, TSH < 0.1) was present in 4 4 % of solitary nodules and in 15 % of MNG. 16.6 % of patients were eu thyroid, and 22.2 % had a TSH < 0.1 and normal free hormones. The 201 Tl scintigraphy, performed instead of the administration of exogenous TSH, showed and uptake of Tl in the remainder of the thyroid. Four typ es of 201Tl uptake were observed in the pathological lobe : type 1 : h omogeneous uptake ; type 2 : heterogeneous uptake and hyperfixation in the nodule ; type 3 : faint uptake and hypofixation in the nodule ; t ype 4 : faint and very heterogeneous uptake. Histological analysis of the nodules showed 32.2 % of follicular adenomas, 25.6 % of MNG and 42 .2 % of colloid nodules. Among these lesions, 70% showed histological signs of hypermetabolism (resorption vesicles...). Multivariate analys is of these data clearly demonstrates the need to redefine the clinica l, biological, scintigraphic and histological concepts of autonomous a denomas. On the other had, 91.6 % of follicular adenomas show a type 2 Thallium uptake (22/24). On basis of these results, we prefer to oper ate these patients rather than to treat them by 1311 or by percutaneou s injection of ethanol.