AGE-RELATED ENDOCRINE TUMORS: NON-FUNCTIONINGADRENAL TUMORS AS COMPARED TO PITUITARYADENOMAS

Abstract

Background. Advances in imaging techniques have led to increasing discovery of adrenal and pituitary “incidentalomas”, tumors with normal endocrine function and no compression mass effects. We evaluated the age at diagnosis (AD) in patients with benign non-functioning adrenal incidentalomas, as compared to pituitary non-functioning tumors, in a series of patients from a national center of endocrinology. Methods. From 2,123 consecutive patients with adrenal and pituitary tumors hospitalized between 1977 - 2009, 2,069 patients were analysed. The study groups included: group A - 137 patients with adrenal incidentalomas (AI), group B - 534 patients with pituitary incidentalomas (PI). Control groups included 1,398 patients: group C1 147 patients with adrenal carcinomas or benign hormone-secreting adrenal tumors, and group C2, 1,251 patients with pituitary secreting adenomas or large non-functioning pituitary macroadenomas (NFA). Imaging was done by computed tomography and/or magnetic resonance after 1981 and by skull X-ray or pneumoencephalography before 1981. Results. Mean age AD is more advanced in patients with AI (53 ± 11.9 years, range 21 - 78 yr) than in patients with PI (36.8 ± 13.1 years, range 10 - 81 yr), p < 0.01. AD was higher in AI than in patients with secreting adrenal tumors, but similar in patients with adrenal malignancy. There is an age-related increase in the proportion of AI among patients with adrenal tumors, and of NFA, but not of PI, among patients with pituitary tumors. In patients aged over 65 years, 74% of patients with adrenal tumors have AI, while only 18% of patients with pituitary tumors have PI and 42% have NFA. AD in NFA (49.3 ± 13.1 yr, range 12 - 79 yr) was more advanced than in PI (p < 0.01). AD does not correlate with tumor size. Tumor growth occurred in 24% of AI (follow-up 3.0 ± 2.8 yr) and only in 0.7% of PI, p<0.01 (follow-up 3.1 ± 2.5 yr). Conclusions. Adrenal non-functioning benign tumors show a clear association with ageing, in contrast with pituitary incidentalomas. It seems unlikely that most pituitary incidentalomas in young patients become large NFA, whose development seems to be also age-related. It is tempting to suggest that pituitary tumorigenesis starts earlier than adrenal tumorigenesis.