Receptor conversion and vocal cord paralysis in a patient with breast cancer

Receptor conversion in breast cancer occurs in up to 32% of patients, resulting in ineffective therapy in the absence of corresponding biomarkers. We report a case of a middle-aged woman who presented with a 2-month history of hoarseness. Laryngoscopy demonstrated right vocal cord paralysis. Whole body positron emission tomography-CT (PET-CT) scan showed a hypermetabolic cervical lymph node, worrisome for metastasis. Biopsy of the cervical lymph node was consistent with metastatic carcinoma of the breast (GATA3 and mammaglobin positive, oestrogen receptor (OR)-positive, progesterone receptor-negative and human epidermal growth factor receptor 2 (HER2)-positive). She underwent targeted therapy with ado-trastuzumab emtansine every 3 weeks. Repeat PET-CT scan after 6 months showed stable disease. Reassessment of receptor status in metastatic breast cancer is encouraged to rule out receptor conversion. There is significant cross-talk between OR and HER2 signalling pathways, leading to treatment resistance. Close collaboration and teamwork among various subspecialties facilitate prompt management of patients with suspected metastatic breast cancer.