Thyroid-stimulating immunoglobulin (TSI) binds to the thyroid-stimulating hormone receptor (TSHR) in orbital tissues, and the resulting immune response leads to periorbital edematous and inflammatory changes, including the infiltration of inflammatory cells, the accumulation of extracellular matrix (ECM) proteins, the proliferation of fibroblasts and increased levels of fatty tissue, resulting in the development of clinical signs of TAO [2]. Here, TSHR is linked to thromboangiitis obliterans.