Endocrine Abstracts

Introduction: CCHD comprises a number of different congenital heart defects associated with elevated pulmonary artery pressure and pulmonary vascular resistance, resulting in a reversed or bidirectional shunt (Eisenmenger syndrome). These entities develop systemic hypoxia. Pheochromocytoma and paraganglioma (PHEO/PG) are neuroendocrine tumours. Several inheritance genetic alterations have been reported in PHEO/PG syndromes. A pathogenic association between these entities is proposed.

Case report: A 41-year-old female diagnosed of a CCHD in the new-born period, on stable medical treatment, as surgery was rejected. She presented with symptoms suggesting exacerbation of heart failure. Catecholamine hypersecretion was suspected; 24 hour urine metanephrine: 215 μg/24 h (NV<341) and normetanephrine (NM): 2491 μg/24 h (NV<444). Abdominal CT showed a retroperitoneal lesion consistent with a PG. Functional imaging with Iodine¹²³MIBG showed a pathological uptake area at the same localization. No other pathological images were observed. Genetic testing was performed and no mutations in SDHD, SDHC, SDHB, VHL, SDHAF2, MAX and TMEM127 genes were found. She underwent surgery after alpha blockade. Pathological examination confirmed the diagnosis of a PG. NM became normal after surgery and patient symptoms improved.

Discussion: Several hypoxemic phenomenon have been related to be implicated in the pathogenesis of PHEO/PG, as it is known that some of the genetic alterations (SDHx, VHL, HIF2) lead to enhanced production of hypoxia inducible factors, which induce an increase in angiogenic factors leading to the development of tumours. The patient had an evolved heart disease with significant cyanosis. Chronic exposure to hypoxia in patients with CCHD could increase the risk for developing PHEO/PG. In addition, the noradrenergic biochemical phenotype found agrees with that observed in some of the PHEO/PG syndromes. In patients with CCHD the diagnosis of PHEO/PG can be difficult to suspect because symptoms may be confounding, nevertheless catecholamine excess may be dangerous. Therefore we consider that the existence of a PHEO/PG should be ruled out in patients with CCHD and aggravation of the previous heart function.