case_images: PMC10882091_01
case_images: Coronal T1-weighted MRI images with contrast enhancement of the pituitary tumor at presentation in 2008 (A) and at last follow-up in 2022 (B).
case_images: fendo-15-1337741-g001.jpg
case_images: PMC10882091_01_fendo-15-1337741-g001.jpg
case_images: f1
case_images: This lesion extended past the sellar floor into the sphenoid sinus, invaded both cavernous sinuses, and was in contact with both optic nerves, anterior to the optic chiasma ( Figure 1 ). His pituitary tumor continued to shrink; after 14 years of treatment, only an intrasellar mucocele remained, with no visible tumor ( Figure 1 ).
case_images: Urinary free cortisol (UFC) concentrations expressed as the number of times the upper limit of normal (ULN), following long-term cabergoline treatment.
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case_images: PMC10882091_01_fendo-15-1337741-g002.jpg
case_images: f2
case_images: Further investigations unveiled an ACTH-dependent hypercortisolism with a UFC = 3,247 microg/24 h (N = 20-60 microg/24 h), 8-a.m. plasma ACTH = 30.2 pmol/L, an abolished cortisol/ACTH circadian rhythm, and an explosive cortisol and ACTH response to the CRH test ( Figures 2 ,  3 ).
case_images: Results of tests evaluating the HPA axis at presentation, during cabergoline treatment, during the transient drug holiday and after cabergoline reinstatement. The tests are, from top to bottom: serum cortisol and plasma ACTH day curve, serum cortisol post dexamethasone suppression test (4-mg test at presentation and 1-mg overnight test at the other evaluations, the shaded area represents the normal suppressed cortisol range), serum cortisol and plasma ACTH during the CRH test, and serum cortisol and plasma ACTH during the desmopressin test. Cortisol concentrations are represented by circles and solid lines, and ACTH concentrations are represented by squares and dashed lines. DST, dexamethasone suppression test; CRH, corticotropin-releasing hormone; NA, not available.
case_images: fendo-15-1337741-g003.jpg
case_images: PMC10882091_01_fendo-15-1337741-g003.jpg
case_images: f3
case_images: Further investigations unveiled an ACTH-dependent hypercortisolism with a UFC = 3,247 microg/24 h (N = 20-60 microg/24 h), 8-a.m. plasma ACTH = 30.2 pmol/L, an abolished cortisol/ACTH circadian rhythm, and an explosive cortisol and ACTH response to the CRH test ( Figures 2 ,  3 ). Remarkably, repeated investigations performed within 22 months of cabergoline therapy showed not only consistently normal UFCs but also restoration of all the cardinal features of the HPA axis function: restoration of a cortisol circadian rhythm, adequate cortisol suppression following the 1-mg dexamethasone suppression test (DST), disappearance of the explosive cortisol/ACTH response to CRH stimulation, and absence of aberrant cortisol/ACTH response to desmopressin stimulation (10 microg IV infusion) ( Figure 3 ). A month later, his prolactin and all biochemical investigations of the HPA axis normalized ( Figure 3 ).