本文报道1例以肢体不自主抖动起病的中年男性，既往有长期饮酒史，发病前1周有上呼吸道感染史，头颅MRI影像提示胼胝体“三明治征”，结合患者的症状、体征及辅助检查结果，诊断为原发性胼胝体变性。通过回顾胼胝体“三明治”征这一特殊影像的病理生理学机制，探讨胼胝体“三明治征”的鉴别诊断思路。

This case reports a middle-aged male patient presented with involuntary limb tremors as the initial symptom. The patient had a history of chronic alcoholism and experienced an upper respiratory tract infection one week prior to symptom onset. Cranial MRI revealed the characteristic of "sandwich sign" in the corpus callosum. Based on the patient's clinical symptoms, physical signs, and ancillary investigations, a diagnosis of primary Marchiaffava-Bignami disease (MBD) was established. By reviewing the pathophysiological mechanism underlying this specific "sandwich sign" imaging finding, this report explores the diagnostic approach for differentiating the "sandwich sign" of the corpus callosum.