[Atypical presentation of a breast cancer pituitary metastasis]

Pituitary metastasis occur in 1-5 % of patients with cancer. We report the discovery of a unique pituitary metastasis of breast cancer. A 67 years old woman was treated in 2003 for local adenocarcinoma. After bone metastatic relapse in 2008, the patient developed diplopia and diabetes insipidus. An MRI revealed a histologically proven metastatic pituitary nodule. Further explorations revealed failure of multiple endocrine axes. Pituitary metastases are relatively rare, but are probably under-diagnosed in the presence of advanced cancers with impaired general condition. This diagnosis should be considered in the context of cancer patients, with a recent history of diabetes insipidus, especially if the latter is associated with other neurological signs (ophthalmoplegia, cephallagia).