Relationship between intrathyroid calcifications and thyroglobulin in endemic goiter

Intrathyroid calcifications represent a common finding within simple or nodular goiters, but, as far as they can be found also inside papillary and medullary thyroid carcinomas, an ultrasonographic detection of intrathyroid calcifications stands as a different diagnosis problem. We have been looking for the presence of parameters associated with thyroid calcifications in patients affected by simple or nodular goiter, either sporadic or endemic. We studied 284 euthyroid subjects, 250 females, ageing from 24 to 90 years, affected by a simple goiter, in the 9.51% of the cases, and by a nodular goiter in the remaining part. 69.37% of the patients came from an endemic goiter area, while the others were affected by sporadic goiter. We tested fT3, fT4, TSH, hTG, Ab-TG, Ab-TPO and performed an ultrasonography in all the subjects. 57.75% of patients shown intrathyroid calcifications in the 57.75% of them. We applied a multistep discriminant analysis taking the presence/absence of calcifications as dependent variable and we tried to find which variable, by itself or in combination with others, could foretell its presence. We also created a new variable (TG1) to differentiate normal from supraphysiologic concentrations of hTG (< 60 ng/ml). The variable with the highest significance F originated from endemic goiter area (F = 96.36), followed by TG1 (F = 24.46) and age (F = 10.61). On the contrary hTG did not relate to calcifications, due to non-proportionally direct relationship between these two parameters, afterwards we used the multistep logistic regression that gave overlapping significances. This means that supraphysiologic hTG rates are sufficient to predict the possible presence of intrathyroid calcifications. In conclusion, as far as a follicular hyperstimulation can be assumed, especially if long-lasting, the presence of intrathyroid calcifications should rise a clinical suspect toward an old goiter rather than a neoplastic lesion.