Retroperitoneal paraganglioma in a patient with Fontan: The hypoxia connection.

Paragangliomas are rare neuroendocrine tumors where hypoxia-inducible factor plays a critical role in tumorigenesis. It has been suggested that patients with congenital heart disease, in particular, may have cellular environment and relative hypoxia favorable to the development of these neuroendocrine tumors. Here, we present a case of an 11-year-old child with hypoplastic left heart syndrome previously palliated with Fontan procedure, diagnosed with paraganglioma on surveillance imaging. We present the clinical course, intervention, and outcome as well as review the possible contributory mechanisms. As we continue to improve long-term survival for single ventricle patients, awareness of these tumors during surveillance may be warranted as timely intervention may lead to cure.