Relationship of each anterior pituitary hormone deficiency to the size of non-functioning pituitary adenoma in the hospitalized patients

Abstract

Non-functioning pituitary adenoma (NFPA) is often associated with hypopituitarism. Diagnosis of hypopituitarism is important because of its poor prognosis and low quality of life. Among hypopituitarism, it is difficult to diagnose secondary adrenocortical insufficiency and GH deficiency without hormone stimulation test. Therefore, the aim of our study was to identify patients with NFPA who require more careful endocrinological examination. We examined the relationship between NFPA size and the prevalence of each hypopituitarism or the response of each anterior pituitary hormone by insulin tolerance test, LHRH test and TRH test. We studied 63 patients with NFPA admitted for evaluation of pituitary function and surgical indication. They were classified three groups by tumor diameter. The prevalence of GH deficiency, male secondary hypogonadism, secondary hypothyroidism and PRL deficiency were higher in the group of larger tumor diameter (p<0.0001, p<0.05, p<0.05 and p<0.05, respectively). However, that of secondary adrenocortical insufficiency only tended to be higher (p=0.07). In the group with small NFPA (less than 20 mm), the prevalence of secondary adrenocortical insufficiency was 38% although those of GH deficiency, male secondary hypogonadism, secondary hypothyroidism and PRL deficiency were 0%, 0% and 8% and 9%, respectively. Anterior pituitary hormone responses except TSH had significantly negative correlation with tumor diameter (ACTH: r=-0.40, GH: r=-0.57, LH: r=-0.69, FSH: r=-0.46, PRL: r=-0.36). The results suggested physicians should proactively suspect GH deficiency, male secondary hypogonadism and secondary hypothyroidism in patients with larger NFPA. On the other hand, adrenocortical function should be examined even in patients with small NFPA.