ABSTRACT

Introduction: Our case discusses a pediatric patient that had an ACTH secreting pituitary adenoma that was not biochemically diagnosed using desmopressin as the stimulating agent for inferior petrosal sinus sampling (IPSS), but as the patient had clinical findings suggestive of Cushing disease, the test was repeated using the gold standard of oCRH as the stimulant, and a pituitary adenoma was identified and subsequently removed.

Case Report: An 8-year-old male presented with physical findings and biochemical evidence of Cushing disease. MRI of the brain revealed a heterogeneous filling defect within the left and right lateral aspects of the pituitary without microadenoma visualized. IPSS was performed using desmopressin as the stimulant for IPSS. The test was negative for ACTH secreting adenoma. IPSS was repeated using the gold standard of oCRH and the patient was found to have Cushing disease.

Conclusion: While desmopressin-stimulated IPSS has shown sensitivity and specificity of over 90% in multiple adult studies and case reports in pediatrics have suggested efficacy, formal pediatric studies have yet to be conducted. Additional studies of desmopressin as a stimulant for pediatric IPSS are warranted and clinicians should be aware of the potential lack of sensitivity of desmopressin stimulated IPSS in pediatric patients.