Authors’ Response: Weight of Normal Parathyroid Glands in Patients with Parathyroid Adenomas

Abstract

We appreciate the thoughtful comments on our paper (1) by Dr. Parfitt (2). We agree that geometric mean would be a more appropriate way to provide a statistical summary of the parathyroid weights but chose the mean weight as had been reported in the five autopsy series of the weights of normal parathyroid glands. As Dr. Parfitt has indicated, this does not affect our conclusion that the weight alone of a parathyroid gland is not sufficient to determine whether a gland is normal. With respect to whether dehydration might account for the differences in gland weights between autopsy and surgical series, we do not know the answer. We have not noted evidence of dehydration in parathyroid glands at autopsy. In more than 3000 cases at the Massachusetts General Hospital, the incidence of double adenomas of the parathyroid was 1.2%, and in the next largest series at the Mayo Clinic it was 1.9% (3). Nevertheless it is possible that very small microadenomas might be detected in higher numbers if serial sections of apparently normal glands were studied. We doubt this would explain our results but will seek approval of our Institutional Review Board to examine the largest normal glands in our series.