Visceral cancer metastasis to pituitary adenoma: Report of two cases

BACKGROUND We report two cases of metastases from visceral cancers to pituitary adenomas, and review the literature. CASE DESCRIPTION Two female patients, aged 75 and 87 years, underwent transesophageal surgery for presumably benign pituitary adenomas. Using extensive immunostaining studies, histopathological examination showed that the surgical specimens from both patients were composed of metastatic deposits within gonadotropin adenomas. Fourteen cases of metastases to pituitary adenomas have been mentioned in 11 reports in the literature. In all cases, the correct diagnosis was made after autopsy or histopathological studies, even in patients known to suffer from visceral malignancies. In our cases, immunohistochemical studies were conclusive in characterizing the two distinct tumor components. The pathogenetic mechanisms favoring the development of metastases in pituitary adenomas are discussed, especially those altering the normal hypophyseal circulation. CONCLUSION Neurosurgeons performing pituitary surgery should be aware of the possibility of metastases in pituitary adenomas. (C) 2001 by Elsevier Science Inc.