[Pituitary metastasis presenting as diabetes insipidus: a report of four cases and literature review].

INTRODUCTION: Pituitary metastases are a rare cause of central diabetes insipidus and usually complicate advanced cancers. CASE REPORTS: We report four cases in which diabetes insipidus revealed a metastatic stage of a lung (two cases) or a breast (two cases) cancer. One patient presented with a panhypopituitarism, three had diabetes insipidus including one with corticotroph insufficiency. In one case, the cerebrospinal fluid analysis showed a lymphocytic meningitis. On brain magnetic resonance imaging there was an absence of high intensity signal in the posterior pituitary lobe (one case) or an infiltration of the posterior lobe (three cases).
CONCLUSION: Breast and lung malignancies are the most frequent causes of metastasis of the pituitary gland. In most cases there are often other metastatic locations; however insipidus diabetes can reveal the metastatic stage of the cancer. A pituitary biopsy may be necessary to obtain the diagnosis.