Amphiphysin expression in a case of occult cancer with paraneoplastic stiff‐person syndrome

The evaluation of the amphiphysin expression in the metastatic lesion was helpful for the diagnosis of paraneoplastic Stiff‐Person syndrome associated with occult breast cancer. Our image may support to realize that the expression of amphiphysin in the metastatic lesion caused this rare symptom. Occult cancer is not rare in paraneoplastic syndromes, so we believe that the assessment of auto‐antigen expression in the metastatic lesion may help our diagnosis and treatment.