About One-Third of Incidental Pituitary Microadenomas Grow

TUESDAY, Feb. 28, 2023 (HealthDay News) -- For patients with incidental pituitary microadenomas, about two-thirds remain unchanged or decrease in size, with any growth occurring slowly, according to a study published online Feb. 28 in the Annals of Internal Medicine.

Dawid Hordejuk, from Brigham and Women's Hospital in Boston, and colleagues conducted a retrospective, longitudinal, cohort study involving 414 patients with evidence of pituitary microadenomas from magnetic resonance imaging (MRI) identified from 2003 to 2021 to assess the change over time.

The researchers found that 78, 49, 34, and 16 of the 177 patients who had more than one MRI had no change in the size of the microadenoma over time, an increase in size, a decrease in size, and both an increase and a decrease in size, respectively. The estimated slope was 0.016 mm/year by linear mixed-model analysis. Pituitary adenomas with a baseline size of 4 mm or less tended to increase in size, with an estimated slope of 0.09 mm/year. In contrast, the size tended to decrease for those with baseline tumor size greater than 4 mm, with an estimated slope of −0.063 mm/year.

"These findings suggest that less frequent pituitary MRI surveillance for patients with incidental pituitary microadenomas may be safe," the authors write. "We recommend repeating a pituitary MRI one year after the initial MRI. If there is no change in the pituitary lesion, we recommend that the next MRI be done three years after the second MRI."

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