What happened, in summary

A 68-year-old woman developed a persistent dry cough and lost about 6 kg over 6 months. She had been treated for a 3 cm grade 2 invasive ductal cancer of the right breast in 1998. None of 10 lymph nodes contained cancer. She underwent right mastectomy and then took tamoxifen for 5 years.

New lung changes raised concern for recurrence, but a wedge resection showed organising pneumonia and no malignancy. She was treated with prednisolone for presumed cryptogenic organising pneumonia. After 12 weeks, breathlessness worsened, bilateral lung nodules progressed, and a pleural effusion appeared. Pleural fluid contained ER- and GATA3-positive atypical cells suspicious for breast-cancer spread. Repeat bronchoscopy then confirmed malignant cells from metastatic breast cancer.

First-line hormone therapy was started for the recurrence. After 12 months, she had significant clinical and radiological improvement, and treatment was continuing.