Metastatic breast cancer masquerading as a pituitary macroadenoma: A case report.

The purpose of this manuscript is to report a case of symptomatic breast cancer metastasis to the pituitary gland, a described yet exceedingly rare phenomenon. A 52-year-old woman with a known history of stage-IV breast cancer treated 3 years prior with chemotherapy presented to the emergency department with 2 weeks of right-sided periorbital headache and 1 week of right-sided ptosis. Magnetic resonance imaging showed a 1.9 cm × 2.8 cm × 2.8 cm mass in the pituitary with mass effect on the right optic chiasm. Endocrine laboratory studies were largely normal, including prolactin, thyroid-stimulating hormone, insulin-like growth factor, and a minimally decreased cortisol. She underwent endoscopic transnasal transsphenoidal resection 4 days later to remove the mass without complication. Postoperative pathologic studies were positive for breast cancer metastasis, and she was subsequently started on adjuvant radiation and oral chemotherapy. While breast cancer metastases to the sella have been described in the literature before, symptomatic spread to the pituitary represents a small percentage of all breast cancer metastases, and we thus feel is worthy of further discussion.