Combined pituitary hormone deficiency and PROP-1 mutation in two siblings: a distinct MR imaging pattern of pituitary enlargement.

Mutations of the PROP-1 gene are the most frequent genetic defect in patients with combined pituitary hormone insufficiency. We present the cases of 2 siblings with PROP-1 mutations whom we observed longitudinally. Their initial pituitary MR imaging examinations showed identical findings: an enlarged adenohypophysis, with striking hypointensity on T2-weighted images and slight hyperintensity on T1-weighted images. In one of the children, the follow-up MR imaging obtained 3 years after hormonal replacement revealed a decrease in the size of the anterior pituitary lobe.