Triple-negative metastatic breast cancer with pituitary metastasis: symptom relief after debulking

What happened, in summary

This 66-year-old woman had a history of both breast cancer and colon cancer. About 10 years before her most recent presentation, she had been treated for left-sided breast cancer with curative intent, including surgery, adjuvant radiotherapy, and letrozole. During later follow-up, metastatic disease was found in several places, including the liver, left orbit, bones, right breast, and pituitary gland. She then developed double vision, worsening bilateral visual disturbance that was more prominent on the right, headaches, excessive thirst, and frequent urination. Pituitary MRI showed a heterogeneously enhancing lesion measuring 24 x 16 x 26 mm, extending into the suprasellar compartment and compressing the optic chiasm. Imaging also showed adjacent skull and clival involvement and a left retro-bulbar mass affecting the optic nerve region. The pituitary lesion had initially been suspected to be a macroadenoma, but the skull base team recommended transsphenoidal endoscopic debulking because of the risk of irreversible vision loss. During surgery, tumor tissue was removed en bloc, and the procedure was uneventful. Histology confirmed metastatic cancer consistent with pleomorphic lobular carcinoma of breast origin. Biomarker testing showed ER-negative, PR-negative, and HER2-negative disease, with no HER2 amplification and a HER2/CEP17 ratio of 1.07. After surgery, her visual fields improved, and her visual symptoms completely resolved. A follow-up MRI 6 months after the procedure showed no recurrence at the pituitary site, and clinical examination was reassuring. Her course after surgery was therefore one of strong local symptom control at the pituitary site while continuing to live with metastatic breast cancer involving other parts of the body.