When to stop monitoring pituitary stalk thickening?

Pituitary stalk thickening (PST) in adults may arise from neoplastic, inflammatory, infectious, or congenital disease, yet the underlying cause frequently remains undetermined after initial evaluation. For patients without an established diagnosis, no adult-specific data defines how long magnetic resonance imaging (MRI) surveillance should be maintained. Current expert reviews recommend early reassessment at 3-6 months, followed by longitudinal imaging for approximately 3-5 years. Among initially indeterminate lesions, spontaneous regression is more likely than the progression, although late diagnosis of histiocytic disease can nevertheless occur. We suggest reducing MRI frequency after sustained stability and considering discontinuation only in carefully selected low-risk adults, while maintaining longer surveillance whenever endocrine, radiological, or systemic risk features persist.