Bilateral pheochromocytoma in patients with von Hippel–Lindau syndrome: clinical and molecular genetic features

Abstract

Bilateral adrenal pheochromocytoma (PCС) is extremely rare in children, with major predisposing factors being multiple endocrine neoplasia type 2 and von Hippel–Lindau syndrome. In case of bilateral PCC with underlying von Hippel–Lindau syndrome, organ-preserving surgery is preferred in view of the low malignant potential of such neoplasms. We aimed to study clinical and molecular genetic features of patients with bilateral adrenal PCCs treated at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Ministry of Healthcare of the Russian Federation. The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Ministry of Healthcare of the Russian Federation. The study included 20 patients with paraganglioma (PGL)/PCC (PPGL) who had received treatment (n = 17) or outpatient care (n = 3) at the Center over the period from 2012 to 2023. Bilateral adrenal PCC was diagnosed in 4 (20%) patients. In all these cases, the diagnosis was confirmed by histology. Molecular genetic testing was carried out at the Laboratory of Molecular Biology at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Ministry of Healthcare of the Russian Federation in order to search for germline pathogenic variants in PCC/PGL susceptibility genes. The median age of the four patients with bilateral adrenal PCC was 9.5 years (range 4.5–14.6 years). All the patients were male. In one patient, synchronous bilateral PCC/PGL was observed. In 100% of the cases, arterial hypertension was diagnosed at the onset of the primary disease and was treated with alpha-blockers as part of preparation for surgery. According to the results of a 24-hour urine biochemistry test, all the patients had at least a 4-fold increase above the upper limit of normal for normetanephrine levels. Molecular genetic testing using the multiplex ligation-dependent probe amplification method revealed a pathogenic germline variant in exon 3 of the VHL gene in all the children (4/4). Hereditary PPGL was proven in 2/4 (50%) patients. In all the cases, R0/R1 resection was achieved. Organ-sparing surgery on one/two adrenal glands was performed in 3/4 cases. One out of four (25%) patients developed a local relapse 18.4 months after diagnosis. The overall survival rate in this group was 100%, with a median follow-up time of 8.1 months (range 0.8–50.2 months). Bilateral adrenal PCC is a very rare childhood tumor. A medical genetic consultation is necessary to identify tumor predisposition syndromes. A multidisciplinary team discussion of a surgical strategy is recommended, with organ-sparing surgery on one or two adrenal glands being the treatment of choice that should be carried out at centers specializing in pediatric surgical oncology. Here, we report a rare clinical case of bilateral retroperitoneal PCC/PGL in a patient with von Hippel-Lindau syndrome. The patient's parents gave consent to the use of their child's data, including photographs, for research purposes and in publications.