Endocrine Abstracts

An 18 year old young man was first seen in the ENT department with bilateral swelling of the supraclavicular fossae. A clinical diagnosis of Cushing's syndrome was made and the patient was referred to the Endocrine team. Examination showed a BP of 150/100 and clinical features of gross Cushing's syndrome. Initial investigations revealed normal electrolytes, fT4 8.7 pmol/L, TSH 0.69 mIU/L and a basal prolactin of 68280 mIU/ml. A 24 hr urinary free cortisol (UFC) was 3860 nmol/L. Cortisol day curve showed a 9am cortisol of 809 nmol/L, 10pm cortisol of 716 nmol/L and a 9am ACTH of 144 ng/L. After a high dose dexamethasone suppression test, his 9am cortisol was 247 nmol/L and UFC 371 nmol/L, suggesting Cushing's disease. An MRI showed a large pituitary mass with minimal suprasellar extension and very little normal pituitary tissue. The patient was commenced on bromocriptine but developed skin rash and arthralgia and was therefore switched to cabergoline 500 mcg twice weekly. Four weeks later, he was admitted for repeat tests including a cortisol day curve and to start metyrapone therapy for Cushing's. During his admission, it was noted that the patient physical appearance had improved dramatically. Clinically, it was felt that his Cushing's disease has remitted, and his BP normalised to 105/60 with no postural drop. This was confirmed by his cortisol day curve showing 9am cortisol of 166 nmol/L and 4pm cortisol of 55 nmol/L. Repeat MRI showed 30% reduction in the volume of the pituitary tumour. The case is unusual in that a single pituitary tumour would appear to be responsible for prolactin as well as ACTH secretion. Even more interesting is his response to cabergoline therapy. We would like to discuss the previous literature in this unusual combination of pituitary hormone excess and further management of this patient.