Cushing disease as possible cause of persistent growth failure despite growth hormone therapy in a small for gestational age male.

Growth hormone (GH) therapy in children with small for gestational age (SGA) has been shown to be of significant therapeutic benefit. We report the case of an 11-year-old Caucasian male who developed early adrenarche, hypertension and insulin resistance on GH therapy for SGA and profound short stature (ht -5 SD). This patient demonstrated a poor response to GH therapy and developed physical and biochemical findings of insulin resistance responsive to metformin therapy. He remained hypertensive, however, and continued to have elevated serum dehydroepiandrosterone sulfate levels. Urinary free cortisol excretion was subsequently found to be elevated. The diagnosis of Cushing's disease was confirmed with inferior petrosal sinus sampling and pituitary MRI. The patient underwent partial adenohypophysectomy with resulting normalization of plasma cortisol levels and associated symptoms. Our patient's diagnosis of Cushing's disease was complicated by his past history of poor growth since birth and history of SGA. The signs of Cushing's disease did not overtly appear until GH therapy was initiated to help treat severe short stature. It is possible that the metabolic effects of GH therapy unmasked the presence of underlying Cushing's disease.