ISOLATED PARAGANGLIOMA IN A PATIENT WITH VHL P.L163F MUTATION

A Case of Von Hippel-Lindau Disease With Recurrence of Paraganglioma and No Other Associated Symptoms: The Importance of Genetic Testing and Establishing Follow-Up Policies

Pheochromocytoma and paraganglioma (PPGL) are rare neuroendocrine tumors. Catecholamine production by the tumors leads to high blood pressure. Although most PPGLs are benign, some have metastatic potential. Almost half of PPGLs are caused by germline mutations, and the causative genes are diverse. Von Hippel-Lindau disease (VHL) is an autosomal dominant multisystem tumor predisposition syndrome characterized by central nervous system and retinal hemangioblastomas, clear cell renal cell carcinoma, pancreatic neuroendocrine tumors, and PPGLs. Sometimes VHL presents only as paraganglioma (PGL), making its diagnosis difficult. A male child aged five years and one month was found to have isolated catecholamine-producing PGL in the right renal hilum during evaluation for hypertension. The patient was completely cured by tumor resection, and somatic mutation testing of the tumor revealed no abnormalities. At the age of nine years and 11 months, the patient had a recurrence of PGL in the left border of the abdominal aorta. Comprehensive germline genetic testing was performed and revealed a pathologic missense variant NM_000551.4:c.482G>A p.(Arg161Gln) in the VHL gene. This variant showed loss of heterozygosity in both primary and recurrent tumors by Sanger sequencing, and DNA microarray analysis revealed a monosomy of the entire chromosome 3 where VHL is located. Arg161Gln has been previously reported in several other VHL families, and the symptoms were diverse beyond PPGLs. This case demonstrates the importance of genetic diagnosis with VHL in mind. It was also recognized that this patient needed to be followed for symptoms of VHL other than PGL.