Multiple thyroid cysts may be a cause of hypothyroidism in patients with relatively high iodine intake.
BACKGROUND
Multiple cysts of the thyroid gland have not been recognized as one of the causes of hypothyroidism. Here we present six patients from a region with relatively high iodine intake in whom multiple cysts of the thyroid were associated with hypothyroidism or the development of hypothyroidism.


CONCLUSIONS
All patients were women and ranged in age from 49 to 71. Their thyroids were mildly enlarged, tests for thyroid autoantibodies were negative, and multiple cysts were detected in the thyroid by ultrasonography. By dietary questionnaire their iodine intake was estimated to range from 2 to 10 mg of iodine daily. Otherwise, there was no evidence for disorders or factors associated with hypothyroidism. All four patients who agreed to dietary iodine restriction became euthyroid at approximately 1 month after a low-iodine diet (less than 0.5 mg iodine per day) was started.


CONCLUSIONS
Although these patients were from a region with high-iodine intake and had a relatively high intake compared with most regions of the world, this amount of iodine intake is not associated with hypothyroidism in otherwise healthy persons. Therefore, we propose that multiple thyroid cysts, which we have termed polycystic goiter, is probably a cause of hypothyroidism in patients with a relatively high iodine intake.
Kuma Hospital, Kobe, Japan. kubota@kuma-h.or.jp
Sumihisa
S
Kubota
Mako
M
Fujiwara
Hanae
H
Hagiwara
Naoyuki
N
Tsujimoto
Kazuna
K
Takata
Takumi
T
Kudo
Eijun
E
Nishihara
Mitsuru
M
Ito
Nobuyuki
N
Amino
Akira
A
Miyauchi
D000368:Aged; D003560:Cysts / Q000150:complications*; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000178:diet therapy / Q000209:etiology*; D007455:Iodine / Q000009:adverse effects*; D008875:Middle Aged; D013959:Thyroid Diseases / Q000150:complications*; D013961:Thyroid Gland / Q000000981:diagnostic imaging; D014463:Ultrasonography
D007455:Iodine