Nonfunctioning Pituitary Microadenomas: Should Imaging Interval be Extended? A Large Single-center Cohort Study
Ashley J Han, Elena V Varlamov, Maria Fleseriu
Abstract
CONTEXT: Characterization of the clinical features and natural history of nonfunctioning pituitary microadenomas (NFPmAs) is limited by heterogeneous and small-scale studies. OBJECTIVE: To characterize the clinical presentation and natural history of NFPmAs and evaluate if imaging follow-up interval can be extended. METHODS: Retrospective single-center cohort study (years 2006-2021) of conservatively managed patients with NFPmAs. Initial symptoms, pituitary function, and tumor size were assessed. A change in NFPmA size ≥2 mm, as determined by pituitary or brain magnetic resonance imaging (MRI), was considered significant. RESULTS: There were 347 patients in the study cohort. Headache (78.4%) and fatigue (70.0%) were commonly reported despite no evidence of mass effect or significant pituitary hypofunction. Pituitary deficiencies at baseline were rare, with hypogonadism being most common (5.1%). During a median imaging follow-up period of 29 months (range 3-154), 8.1% of NFPmAs grew. Growth incidence was 2.1 per 100 person-years with a mean and median time to growth of 38.1 (SD ± 36.4) and 24.5 (interquartile range 12.0-70.8) months, respectively. Tumor growth was mild and not associated with new pituitary deficiencies or visual deficits. CONCLUSION: These data indicate that the natural history of NFPmAs is overall benign. Consequently, we propose that the initial MRI follow-up timeline for NFPmAs can be extended up to 3 years unless a lesion is close to the optic chiasm, there are worrisome mass effect symptoms, or new pituitary deficiencies.