Abstract
A 45-year-old woman presented with persistent bilateral breast and axillary pain lasting for more than 3 months. Lengthy work-up failed to identify the etiology. Physical examination was entirely normal, including breast examination. A traditional Kampo medicine, Goshaku-san, was tried, and the symptoms began to improve gradually. This case is characterized by persistent regional pain syndrome mainly on her breast yet not accompanied by other symptoms, and we would like to propose the current case as a novel unique disease entity. We also discuss the potential benefit of Kampo medicine for the symptoms.