Endocrine Abstracts

Variability is common, if not omnipresent, in cortisol excess. So-called “cyclic Cushing’s syndrome” (cCS) refers to a subset of patients in whom periods of glucocorticoid excess (peaks) spontaneously alternate with periods of low or normal cortisol concentrations (troughs). cCS is marked by diagnostic errors, and possibly poorer outcomes. In this talk, I will provide an overview of different cortisol secretion kinetics, with a particular focus on the diagnostic challenges encountered in both adult and pediatric patients. Drawing on new data from our international patient cohort – collected from expert centers worldwide – I will offer practical guidance for improving diagnosis and patient care. Using case-based examples, I will highlight common diagnostic pitfalls and how to avoid them. I will present novel findings on cortisol secretion patterns and explore associated clinical and biochemical outcomes in patients with cCS. Finally, I will discuss potential underlying mechanisms of cyclicity and offer an outlook on ongoing and future research directions.

Key questions addressed in this talk: • To cycle or not to cycle:(How) can we distinguish cortisol variability from true cyclic Cushing’s syndrome?

• What are the main diagnostic pitfalls in cyclic Cushing’s syndrome, and how can we avoid them?

• What is the optimal treatment approach for patients with (suspected) cyclic Cushing’s syndrome?

• Is cyclicity unique to the corticotroph axis, and what mechanisms might explain it?

What are the future directions of research on cyclic Cushing’s syndrome?