Paraganglioma of the organ of Zuckerkandl associated with a somatic HIF2α mutation: A case report.

Paragangliomas of the organ of Zuckerkandl (OZ-PGL) are rare tumors that, in >70% of cases, occur in association with succinate dehydrogenase complex iron sulfur subunit B (SDHB) or SDHD gene mutations. The aim of the current study was to determine whether a somatic genetic defect in the hypoxia-inducible factor 2α (HIF2α) gene was present in a case of sporadic OZ-PGL. A 32-year-old African female presented with uncontrolled hypertension during the first trimester of pregnancy. A diagnostic hysteroscopy was performed 3 months after delivery, precipitating a hypertensive crisis. Thereafter, the patient was diagnosed with noradrenaline-secreting OZ-PGL. A complete blood count identified mild normocytic anemia of an inflammatory origin. Surgical removal of the tumor resulted in normalization of plasma and urinary normetanephrine levels. Genetic testing for germline mutations (including large deletions) in the von Hippel-Lindau tumor suppressor, SDHB, SDHC and SDHD genes was normal. However, a heterozygous missense mutation (c.1589Cys>Tyr) was detected in exon 12 of HIF2α, which results in a substitution of alanine 530 with valine (Ala530Val) in the HIF2α protein. A germline mutation was excluded based on the negative results of blood DNA testing. A three-dimensional homology model of Ala530Val was constructed, which showed impaired HIF2α/VHL interaction and decreased HIF2α ubiquitination. 1H-high-resolution magic-angle-spinning nuclear magnetic resonance spectroscopy detected low succinate levels and high α and β glucose levels. To the best of our knowledge, the present case represents the first of its kind to associate a somatic HIF2α gain-of-function mutation with OZ-PGL. It is therefore recommended that patients without germline SDHx mutations should be tested for HIF2α mutations.