European Journal of Biomedical and Pharmaceutical Sciences

NOETERIC ACUMEN INTO POLYCYTHEMIA, PARAGANGLIOMA, AND SOMATOSTATINOMA: PACAK ZHUNG SYNDROME

*Dr. L. Siddhartha, Ch. Sushmita, P. Anusha, P. Ajay and Ravali D.

ABSTRACT

A new syndrome of paraganglioma, somatostatinoma, and polycythemia has been discovered (known as Pacak–Zhuang syndrome). This new syndrome, with somatic HIF2A gain-of-function mutations, has never been reported in male patients. We describe a male patient with Pacak–Zhuang syndrome who carries a newly discovered HIF2A mutations. Somatic gain-of-function mutations in the gene encoding HIF-2a were reported in patients with paraganglioma and polycythemia and have been found exclusively in female patients. Through sequencing of the HIF2A using DNA from paraganglioma in 15-year-old male patient, we identified a novel mutation of HIF2A: a heterozygous C to A substitution at base 1589 in exon 12 of HIF2A. The mutation was not found in germline DNA from leukocytes. This study provides detailed information about the clinical aspects and course of 7 patients with this syndrome and brings into perspective these experiences with the pertinent literature. Six females and one male presented at a median age of 28 years (range 11–46). Two were found to have HIF2A somatic mosaicism. No relatives were affected. All patients were diagnosed with polycythemia before age 8 and before PGL/SOM developed. PGLs were found at a median age of 17 years (range 8–38) and SOMs at 29 years (range 22–38). PGLs were multiple, recurrent and metastatic in 100, 100 and 29% of all cases, and SOMs in 40, 40 and 60%, respectively. All patients had abnormal ophthalmologic findings and those with SOMs had gallbladder disease. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed cystic lesions at multiple sites and hemangiomas in 4 patients (57%), previously thought to be pathognomonic for von Hippel-Lindau disease. The most accurate radiopharmaceutical to detect PGL appeared to be [18F]-fluorodihydroxyphenylalanine ([18F]-FDOPA). Therefore, [18F]-FDOPA PET/CT, not [68Ga]-(DOTA)-[Tyr3]-octreotate ([68Ga]-DOTATATE) PET/CT is recommended for tumor localization and aftercare in this syndrome. The long-term prognosis of the syndrome is unknown. However, to date no deaths occurred after 6 years of follow-up. Physicians should be aware of this unique syndrome and its diagnostic and therapeutic challenges.

Keywords: Hypoxia-inducible factor, tumorigenesis, pheochromocytoma, paraganglioma, Pacak-Zhuang syndrome.