Endocrine Abstracts

Introduction: Pituitary metastases occur in 1% to 4% of cancer patients in autopsy studies. The most frequent primary tumors are breast and lung tumors. Renal cell carcinoma (RCC) is a rare cause of pituitary metastases, with only 25 previously reported cases.

Case report: A 77-year-old-man was admitted to our hospital because of acute progression of chronic renal failure presenting with appetite and weight loss in August 2014. He underwent hemodialysis. His fasting blood glucose was low without any symptoms. In 1998, he had undergone left nephrectomy and adrenalectomy, and was diagnosed with a clear cell RCC. In 2001, lung metastasis was diagnosed and he was treated with interferon therapy, which led to remission. In 2009, lung metastasis was observed again, but he declined treatment. He had hyperprolactinemia and hypopituitarism; levels of PRL: 292.8 ng/ml, free T4: 0.56 ng/ml, TSH: 0.953 μIU/ml, cortisol: 2.0 μg/ml, ACTH: 5.4 pg/ml, IGF1: 42 ng/ml. Magnetic resonance imaging revealed a 7×8×9 mm mass with a pituitary stalk that compressed the optic chiasm without visual disturbance. Dynamic tests showed hyporesponses of cortisol, LH, FSH, TSH, and GH. We considered pan-hypopituitarism due to pituitary stalk metastasis from RCC but could not diagnose it histologically. Diabetes insipidus was not recognized, probably owing to renal failure. Hormone replacement was started with hydrocortisone and L-thyroxine; his hypoglycemia and anorexia improved. In September 2015, he died of pneumonia. The autopsy showed that the clear cell RCC had spread to the thyroid gland, right lung, and pancreas in addition to the pituitary stalk.

Conclusion: We reported a case of a hemodialysis patient presenting with a symptomatic pituitary metastasis from RCC. It is difficult to distinguish symptoms of hypopituitarism from nonspecific symptoms in a hemodialysis patient. In this case, we diagnosed an extremely rare pituitary stalk metastasis by autopsy.