Dramatic Recovery of Vision after Trastuzumab Deruxtecan Treatment of HER2-Positive Breast Cancer with Pituitary Metastasis.

In recent years, both the number of patients with breast cancer and those with associated brain metastases (BMs) have increased. Human epidermal growth factor receptor 2 (HER2)-positive breast cancer has a high BM frequency. The prognosis of BM from breast cancer is poor, and establishing effective treatment for this disease is essential.