Impaired iodide organification in autonomous thyroid nodules.
BACKGROUND
The clinical evolution of autonomous thyroid nodules (ATN) is unpredictable, and thyrotoxicosis is observed at variable nodule size. In vitro data suggest that hydrogen peroxide production is decreased in ATN, indicating intranodular iodide organification impairment.


OBJECTIVE
We aimed to determine iodide organification efficiency in ATN and its relationship with thyroid status in patients.


METHODS
Forty-six patients with a single ATN on the 123I thyroid scan were included in the study. Biological evaluation and iodine perchlorate (I-ClO4) discharge test were carried out in all subjects.


METHODS
The study took place at an academic hospital.


RESULTS
Among the 46 patients, 28 patients (61%) had a positive I-ClO4 discharge test with a mean +/- sd value of discharge of 42 +/- 13%, and 18 (39%) had a negative discharge test with mean +/- sd of 5 +/- 9%. In the group of patients with a negative discharge test but not in the group with a positive test, serum-free T3 and free T4 concentrations were significantly correlated with the 123I uptake. The severity of hyperthyroidism was not different between both groups.


CONCLUSIONS
Intranodular iodide organification was impaired in most patients with ATN. Whether differences in organification capability could predict the risk for evolution to overt hyperthyroidism in patients with ATN remains to be established.
Moreno-Reyes
Rodrigo
R
Department of Nuclear Medicine, Hopital Erasme, Université Libre de Bruxelles, route de Lennik 808, 1070 Brussels, Belgium. rmorenor@ulb.ac.be
Tang
Bich-Ngoc-Thanh
BN
Seret
Alain
A
Goldman
Serge
S
Daumerie
Chantal
C
Corvilain
Bernard
B
D000368:Aged; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007453:Iodide Peroxidase / Q000378:metabolism; D007455:Iodine / Q000378:metabolism*; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D010472:Perchlorates; D011877:Radionuclide Imaging; D016606:Thyroid Nodule / Q000000981:diagnostic imaging / Q000378:metabolism*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
D007457:Iodine Radioisotopes; D010472:Perchlorates; D014284:Triiodothyronine; D013972:Thyrotropin; D007455:Iodine; D007453:Iodide Peroxidase; D013974:Thyroxine