[Serum thyroglobulin is elevated in patients with heterogeneous goiter during radioiodide scintigraphy, but normal in those with homogeneous goiter].

Serum thyroglobulin (Tg) levels were determined in 98 biologically euthyroid patients with a diffuse or nodular goiter, and compared to values observed in 33 control subjects. Based on the results of clinical examination and thyroid scanning with radioiodine, patients were divided into 3 groups: group 1 with homogeneous diffuse goiters, group 2 with heterogeneous diffuse goiters without palpable nodules, and group 3 with solitary hypofunctioning nodules. The control group had a mean Tg of 37 +/- 15 micrograms/l. Group 1 (n = 32) had a mean Tg of 46 +/- 28 micrograms/l; six (19%) had an elevated Tg level (level greater than 74 micrograms/l). Group 2 (n = 30) had a mean Tg of 133 +/- 134 micrograms/l; fourteen (47%) had an elevated Tg level. Group 3 (n = 36) had a mean Tg of 188 +/- 191 micrograms/l; twenty (56%) had an elevated Tg level. The comparison of Tg between patient groups, and between patients groups and the control group, showed a significantly higher value in the groups of hypofunctioning nodules and heterogeneous diffuse goiters. It is concluded that the elevated serum Tg level in patients with a diffuse or nodular simple goiter is commonly associated with heterogeneity of the thyroid scan.