VANISHING ACT(H): A CASE OF SPONTANEOUSLY RESOLVING CUSHING’S DISEASE
Introduction & Objectives:
We present the first reported Australian case of spontaneous resolution of Cushing’s Disease (CD). A 20yo woman with no previous medical history was referred to the endocrinology clinic for investigation of galactorrhoea and prolactinaemia (1.5x ULN). An MRI revealed a 10mm pituitary lesion. Cabergoline was commenced to treat galactorrhoea. A clinical and biochemical picture of incipient hypercortisolism unfolded in the following months, culminating in a diagnosis of Cushing’s Disease.
Methods:
Hypercortisolism was confirmed on 1mg DST, MSC and UFC. ACTH-dependence was confirmed with a peripheral corticotropin stimulation testing (CST), and a positive 4mg IV DST suggested CD rather than an ectopic source.
An interval MRI performed six months after the index scan demonstrated an increase in size of the lesion and the patient was referred for neurosurgery following discussion at a pituitary multi-disciplinary meeting. Cabergoline was ceased. However, a pre-operative MRI showed complete resolution of the pituitary mass, culminating in cancellation of pituitary surgery. This was accompanied by complete resolution of the clinical and biochemical features of hypercortisolism, confirmed by serial MST and 24-hr UFC collections which had completely normalised. Repeat MRI and biochemical testing demonstrated continued remission.
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Figure 1
Figure 1 depicts a series of T1 MRI images in the sagittal plane showing the evolution of the pituitary lesion. A: 10mm adenoma at time of diagnosis (January 2023). B: interval increase to 12.5mm (August 2023). C: Complete spontaneous resolution of adenoma (February 2024
Conclusions:
Spontaneous resolution of Cushing’s Disease is rare, and this case adds to a limit number reported in the literature. Although commenced for a separate indication, an inadvertent and serendipitous effect of cabergoline treatment and radiologically occult pituitary apoplexy remain possible causes of the vanishing adenoma in this case.