[Unusual manifestations of autoimmune thyroiditis]

Autoimmune thyroid disease (AITD) is quite common and comprises goitrous and nongoitrous eu- and hypothyroid Hashimoto's Disease with or without preceding thyrotoxicosis, classical hyperthyroid Graves' Disease and its rarer eu- and hypothyroid variants. There is no generally accepted international classification of AITD. Important aspects of the pathogenesis of AITD have been elucidated in the past two decades. AITD may be explained by an excess of either stimulating and/or destructive/blocking immune processes or by a balanced coexistence of various of these pathological autoimmune features. The HLA (DQA1*0501) is involved in determining the susceptibility to AITD. The measurement of antibodies against thyroidal peroxidase and TSH receptor has become the cornerstone in the diagnosis of AITD. Antibodies directed against TSH receptors are stimulating (TSAb) or blocking (TSBAb). In routine measurements they are determined by a radioligand assay which does not distinguish between these two different types of antibodies. A valid interpretation of antibody results is therefore only possible in connection with the clinical findings and the results of thyroid hormone measurements. We present here four unusual cases with AITD which illustrate its complexity and summarize the present state of knowledge on this disease.