Bilateral phrenic nerve paralysis as a manifestation of paraneoplastic syndrome

To a growing list of causes of phrenic nerve paralysis, we report a case of a 58-year-old lady, non-smoker, non-alcoholic, who was referred to the American University of Beirut Medical Center for the management of a locally advanced infl ammatory right breast cancer. Her physical examination revealed a 10 cm tumor in the right breast associated with infl ammatory skin changes all over the right chest wall. She also had right axillary lymphadenopathy that induced severe pain and diffi culty in moving the right arm. Neurologic examination revealed normal cranial nerve function and adequate muscle tone and power in all extremities. The remaining physical examination was unremarkable. Biopsy of the breast lesion revealed poorly differentiated adenocarcinoma with negative hormonal receptors and over-expression of Her-2/Neu. Metastatic work up including positron emission tomography (PET) scan and computerized tomography (CT) scan showed that the tumor was confi ned to the right breast and axilla. She was started on systemic neo-adjuvant chemotherapy and received four cycles of Docetaxel and Trastuzumab with good clinical response. She then received one cycle of FAC (5-fl uorouracil, doxorubicin and cyclophosphamide) chemotherapy with poor tolerance, followed by two cycles of Vinorelbine and Trastuzumab. Before fi nishing her chemotherapy, she started complaining of cough and shortness of breath. A few weeks later she presented with acute onset dyspnea, more in the supine position, that improves in the standing position. On inspiration, the patient’s abdomen moved inward rather than outward. Her chest wall however, moved normally outward. Her respiratory failure required mechanical ventilation which later showed good clinical response; however she could not be entirely weaned off the respirator. A chest radiograph was done and revealed consistently elevated hemidiaphragm on both sides. A chest CT scan was negative for any mediastinal involvement. Electromyography (EMG) and nerve conduction studies showed that phrenic nerve stimulation evoked no responses from either hemidiaphragm. Needle electromyography of the right diaphragm showed a reduction in the number of fi ring motor unit potentials. The clinical and laboratory fi ndings were suggestive of weakness of both leaves of the diaphragm and so she was diagnosed with paraneoplastic bilateral phrenic nerve paralysis with secondary respiratory failure. Later on, she underwent tracheostomy and was put on mechanical ventilation at home using a portable ventilator. After fi nishing neo-adjuvant chemotherapy, the patient underwent preoperative evaluation that showed good radiologic response of tumor with no metastasis. A follow-up EMG showed progression of the phrenic nerve disease. She then underwent a right modifi ed radical mastectomy and axillary dissection with no postoperative complications. The pathology report showed no gross tumor with persistence of microscopic foci of residual ductal carcinoma in situ and metastatic adenocarcinoma (2 mm) to one of 15 axillary lymph nodes. She was then put on adjuvant chemotherapy with Vinorelbine and Trastuzumab for seven cycles and received radiation