Secondary Parkinson disease caused by breast cancer during pregnancy: A case report

BACKGROUND: Paraneoplastic neurological syndrome manifesting as secondary Parkinson disease caused by breast cancer is extremely rare. CASE SUMMARY: We report a 39-year-old primipara of 31 gestational weeks, who presented with worsening tremors, facial stiffness and speech disfluencies, and decreased limb strength. Thorough physical examinations and auxiliary tests suggested secondary Parkinson’s disease, but the pathogenesis was unknown. During the cesarean section at the 31 weeks plus 6 d, an exploration and liver biopsy revealed a metastatic, poorly differentiated adenocarcinoma. The positron emission tomography and immunohistochemical analysis confirmed a breast ductal carcinoma of stage IV. To our knowledge, only two reports have documented the association between the breast cancer and the Parkinson disease, and neither occurred in pregnant women. CONCLUSION: Our case alerts the secondary Parkinson disease as the possible presentation of breast cancer, the most common malignancy during pregnancy.