Pituitary metastasis mimicking a pituitary adenoma. A description of two cases.

The cases of two elderly women treated for temporal hemianopsia due to a large pituitary mass with suprasellar extension are presented. In both cases, the clinical picture, without diabetes insipidus and cranial nerve paralysis, as well the neuroimaging and endocrinological investigation showing hypopituitarism, were suggestive of a non-secreting pituitary adenoma. In the first patient malignant tissue was unexpectedly encountered during transsphenoidal surgery. Anatomopathological investigation confirmed the presence of a metastasis of a breast carcinoma for which she had been treated 17 years earlier. In the second patient, a preoperative chest X-ray before transsphenoidal surgery revealed an asymptomatic bronchial tumour. Subsequently a squamous cell carcinoma with a metastasis in the pituitary was confirmed. These two cases illustrate the fact that a pituitary metastasis can closely mimic a pituitary adenoma. Even in the absence of suggestive symptoms such as diabetes insipidus and/or cranial nerve paralysis the possibility of metastatic disease in the differential diagnosis of a pituitary mass should always be considered.