Pituitary Incidentalomas in the United States: A National Database Estimate

Increasing use of imaging is associated with increasing diagnoses of pituitary incidentalomas (PIs), which often do not require surgical or medical treatment. In this study, we evaluate U.S. incidence, epidemiology, and trends of pituitary adenomas (PAs) and PIs from 2004 to 2018.

A total of 50,220 PAs were selected from the SEER (Surveillance Epidemiology and End Results) 2020 submission. PIs that do not initially require surgical or medical treatment were filtered from PAs if they were best diagnostically confirmed by radiography, not indicated as prolactinomas in physician reports, not recommended surgery initially, and reported a correct tumor size. Age-adjusted incidence rates, patient demographics, tumor characteristics, trends over time, and differences between PAs and PIs were explored.

Between 2004 and 2018, the incidence rates of PAs and PIs were 4.28 ± 0.04 and 1.53 ± 0.02 per 100,000 population, respectively. When observing changes from 2004 to 2018, a nearly 3-fold increase from 0.73 ± 0.05 to 2.00 ± 0.09 per 100,000 was observed for PIs. The proportion of PIs significantly increased from 24.91% of all PA diagnoses in 2004 to 42.07% in 2018 (P < 0.001). When comparing non-PI PAs with PIs, PIs were more commonly diagnosed in females (64.72% vs. 54.27%; P < 0.001) with microadenomas (61.68% vs. 13.37%; P < 0.001).

Reports of increasing PAs in the United States are likely caused by an increase in diagnosing PIs. This result parallels findings from other countries. This national PI estimate may serve as a point of comparison for future studies investigating imaging and PI rates at individual institutions.