ESPE Abstracts

Background: ACTH-independent adrenal Cushing’s syndrome accounts for less than 15% of endogenous Cushing’s syndrome in children. We present a rare case of ACTH-independent adrenal Cushing’s syndrome, which was associated with myoclonic dystonia.

Case presentation: A 12-year old girl was referred on account of rapid weight gain, fatigue, growth deceleration and facial hypertrichosis. She had a history of gait instability and ataxia till the age of 5 years. Clinical examination revealed buffalo hump, moon facies, central obesity, dysmetria and ataxia. Her height was 128.4 cm (<3rd centile), her weight was 32.3 kg (3rd–10th centile) and her BMI was 19.6 kg/m² (25th–50th centile). Her Tanner pubertal stages were B1, P3 and AH1.

Laboratory findings: Endocrinologic evaluation revealed elevated 24-hour urine free cortisol excretion ((1699.9 and 1079.7 (normal values: 2.6–37 μg/day)) and supressed plasma ACTH concentrations (<1 ng/mL) on several measurements. ACTH concentrations remained suppressed throughout a formal CRH Test. A Liddle test showed no suppression of serum cortisol concentrations following stimulation with low dose (22.47 μg/dl) and high dose (27.95 μg/dl) dexamethasone. The rest of the endocrinologic investigations were normal. A computed tomography scan of the adrenals showed increased adrenal volume bilaterally. The diagnosis of ACTH – independent Cushing’s syndrome was made and the patient underwent bilateral adrenalectomy. The histopathologic examination confirmed isolated micronodular adrenocortical disease. The patient has been on replacement therapy with hydrocortisone and fludrocortisone since. Neurological evaluation confirmed the diagnosis of myoclonic dystonia due to deletion of the SGCE gene.

Conclusions: Exogenous Cushing’s syndrome is the commonest aetiology of Cushing’s syndrome in the pediatric population. Isolated micronodular adrenocortical disease is an extremely rare aetiology of ACTH-independent Cushing’s syndrome and bilateral adrenalectomy remains the best therapeutic option. Our case represents the first case of isolated micronodular adrenocortical disease associated with myoclonic dystonia.