8263 Long-term Imaging Follow-up of Non-functioning Pituitary Adenomas
Authors: Mehrotra Neha , Ross Madeline M , Chilukuri Akanksha S , Eljamri Soukaina , Ewing Caroline , Patel Suraj , Patel Vaidehi , Siegel Lauren B , Sistla Divya , Shariff Rimsha K , Fazeli Pouneh K 
Published: October 2024

Disclosure: N. Mehrotra: None. M.M. Ross: None. A.S. Chilukuri: None. S. Eljamri: None. C. Ewing: None. S. Patel: None. V. Patel: None. L.B. Siegel: None. D. Sistla: None. R.K. Shariff: None. P.K. Fazeli: None.

Pituitary adenomas are common, affecting ∼15% of the population. Once a pituitary adenoma has been identified on imaging, an evaluation is undertaken for pituitary hormone excess and for pituitary hormone deficiency in the setting of larger adenomas (typically 1cm in size or greater). Hormone-producing or functioning pituitary adenomas are typically treated with medical or surgical therapy, but non-functioning pituitary adenomas can be followed conservatively if they are not contributing to morbidity. The natural history of non-functioning pituitary adenomas has not been well characterized and therefore although guidelines recommend follow-up pituitary imaging, there are no specific guidelines addressing how frequently or for how long these lesions should be followed. Our aim was to describe the clinical history of non-functioning pituitary adenomas using long-term clinical data from a large academic health system. We identified 791 patients who met our inclusion criteria of having more than one brain/pituitary MRI performed at least 3 months apart with a suspected non-functioning adenoma identified on the initial MRI. Each medical record was individually reviewed to confirm whether the adenoma was non-functioning based on clinical/biochemical evaluation. Patients were a median [interquartile range] of 48.3 [34.4, 63.6] years of age at the time of first MRI and 65% (n=517) were women. At presentation, 66% (n=523) of the pituitary adenomas were microadenomas (&lt; 1 cm in size) and 34% were macroadenomas (&gt; 1 cm). All patients had an MRI repeated at least 3 months after the initial MRI with median time of total imaging follow-up of 39.8 [17.0, 75.6] months. During follow-up, 658 patients were noted to have a stable lesion or a decrease in size of the adenoma. Patients whose lesion was noted to grow on MRI were slightly older than those who did not have growth (growth: 57.1 [41.9, 70.3] years versus no growth: 46.8 [33.7, 62.3] years, p&lt; 0.0001). There were no differences with respect to BMI, hypopituitarism, smoking history or alcohol use between those with growth versus those without growth. Seventy-eight patients (9.9%) had surgical resection of their adenoma during follow-up. The most common indication for surgery was growth of the lesion (n=27), followed by visual changes (n=22). In the patients with a microadenoma at presentation, 90.8% remained stable in size or decreased in size during a median follow-up of 43.2 [20.5, 78.6] months. Only 2.3% of patients with a microadenoma at presentation underwent surgical resection during follow-up. In conclusion, the majority of non-functioning pituitary adenomas remain stable during prolonged imaging follow-up. Further study is needed to determine predictors of growth of non-functioning pituitary adenomas.

Presentation: 6/2/2024