Evidence of integrity of the follicular basement membrane in Hashimoto's thyroiditis

The basement membrane as an antigenic structure in autoimmune diseases has been a matter of controversy. The purpose of our study was to determine pos sible structural changes in the follicular basement membrane (FBM) in thyro id autoimmune and non-autoimmune diseases. Immunohistochemical staining for collagen IV and laminin showed that the continuity of the FBM was preserve d in toxic adenoma (three cases), atoxic multinodular goiter (nine cases) a s well as in autoimmune disease. Integrity of the FBM was observed in all 1 1 cases of Graves' disease and Hashimoto's thyroiditis (seven cases) studie d. In some instances, the FBM was thinned in areas of contact with inflamma tory infiltrate. We conclude that the auto-antibodies, and possibly other f actors present in autoimmune thyroid diseases, do not significantly alter t he integrity of the FBM.