Endocrine Abstracts

Objective: To assess the association between empty sella (ES) and primary autoimmune hypothyroidism, and the possibility of a common pathogenesis.

Patients and methods: We retrospectively studied all patients with presumed ES diagnosed in the last 20 years, most of whom were treated and followed up by our Endocrinology Department. Subjects with a known aetiology were excluded. Incomplete records or those with a doubtful diagnosis were also excluded. A total of 56 subjects were included in the study. ES was diagnosed by pituitary MRI. The measurement of free T4, TSH, and antithyroid antibodies (TPOAb and TgAb) was assayed using commercial kits. Hypothyroidism was defined as a serum TSH titer higher than 10 μU/ml and/or FT4 less than 0.6 ng/dl. Subclinical hypothyroidism was defined as a serum TSH titer of 4.5 to 10 μU/ml and normal FT4.

Results: Fifteen (26.78%) patients of 56 with ES had autoimmune thyroid disease (6 with primary hypothyroidism, 6 with subclinical hypothyroidism, and 3 with normal FT4 and TSH values). Primary hypothyroidism with negative antithyroid autoantibodies was found in a further 13 patients (23.21%).

Conclusions: There is an important association between ES and autoimmune thyroid disease, which reached 26.78% in our series. The percentage would probably be higher if the antithyroid antibody test had been performed in all cases of hypothyroidism. We suggest the possibility of a common pathogenesis for certain cases of ES and autoimmune thyroid disease, in which ES may occur as the natural progression of autoimmune hypophysitis more or less simultaneously with autoimmune thyroid disease, with the end point of ES in the pituitary and atrophy in the thyroid gland. Advances in laboratory methods for antipituitary autoantibody determination would help to resolve this question.