Insulin-mediated pseudoacromegaly: a report of two pediatric patients.

BACKGROUND: Insulin-mediated pseudoacromegaly is a rarely described pediatric phenotype. We present two patients displaying excessive growth associated with marked acanthosis nigricans, hyperinsulinemia and metabolic dysregulation. CASE PRESENTATION: Both patients, of First Nations descent, presented with excessive growth - patient one at 3.92 years (height z-score +3.75) and patient two at 9.0 years (height z-score 5.15). Insulin-like growth factor-1 (IGF-1) levels were normal with appropriate growth hormone suppression, yet marked hyperinsulinemia. Prepubescent growth velocities exceeded 9 cm/year, resulting in final adult height predictions exceeding 3 standard deviations (SDs) of predicted. Clinical courses were complicated by type 2 diabetes, marked acanthosis nigricans and long-standing psychosocial distress. CONCLUSIONS: Pediatric patients with insulin-mediated pseudoacromegaly are at risk of significant physical, metabolic and psychosocial comorbidities. Unlike adults, the implications in childhood prompt consideration for therapies to decelerate linear growth and avert progression to metabolic dysregulation. Increased recognition of this condition may improve pathophysiological understanding, diagnostic criteria and therapeutic options.