Clinical Presentation and Pathologic Characteristics of Pituitary Metastasis from Breast Carcinoma: Cases and a Systematic Review of the Literature

Background: It is rare for breast carcinoma to metastasize to the pituitary gland; this finding indicates extensive metastasis of the primary tumor.

Case Description: Herein, we present a 57-year-old patient with pituitary gland metastasis from breast cancer that was treated with extensive radical mastectomy 16 years prior. The pituitary was the sole site of metastasis. The patient was admitted with the chief complaint of blurred vision for 1 year and episodic headaches for 1 month. Magnetic resonance imaging revealed a solid mass in the sellar region with heterogenous contrast enhancement. The preoperative diagnosis was a pituitary adenoma. Neuroendoscopy-assisted tumor resection was conducted through a single-nostril sphenoid sinus approach. A pinkish-white, firm neoplasm was found, with an abundant blood supply and an indistinct boundary between the neoplasm and normal pituitary tissue; complete resection was achieved. The results of immunohistochemical analysis were positive for cytokeratin, Ki-67antigen, estrogen receptors, progesterone receptors, and prolactin-induced protein. The neoplasm was negative for spalt-like transcription factor 4, mammaglobin, and the alpha subunit of the glycoprotein hormones. These results were used to reach a final diagnosis of pituitary gland metastasis from a primary breast carcinoma. The patient's vision improved significantly after surgery, and no recurrence was detected during 1 year of follow-up.

Conclusions: Pituitary gland metastasis is rare and difficult to differentiate from a pituitary adenoma without a pathologic diagnosis. Surgery is the first choice for treatment. Surgery, radiotherapy, and chemotherapy are combined with endocrine therapy to tailor treatment to the results of immunohistochemistry.