A Young Patient with Undiagnosed Polycythemia-Paraganglioma Syndrome: A Case Report.

BACKGROUND Erythrocytosis results from primary or secondary causes and is characterized by an increased red blood cell count. Secondary erythrocytosis is a result of an underlying cause outside the bone marrow and is often mediated by erythropoietin. Paragangliomas are rare tumors characterized by increased release of catecholamines with symptoms such as hypertension, hematuria, headache, sweating, and post-micturition syncope. Polycythemia-paraganglioma syndrome (PPS) is exceedingly rare, and reports in the literature are limited. CASE REPORT A 14-year-old female patient presented to our clinic with sweating, palpitations, and palmar erythema. The patient's history was significant for uninvestigated hypertension diagnosed at the age of 9. There was no history of smoking or illicit drug use. Blood investigations revealed an elevated hemoglobin level of 18.5 g/dL and a hematocrit of 57.5%. Whole-genome sequencing found no mutations, excluding polycythemia vera from the differential diagnosis. Computed tomography (CT) revealed 2 lesions compatible with urinary bladder paragangliomas and retroperitoneal lesions, likely representing metastatic lymphadenopathy. Whole-body gallium-68 DOTATATE PET/CT scan demonstrated significant tracer uptake within the necrotic retroperitoneal lymph nodes. However, evaluation of the bladder lesion was limited due to physiological urinary excretion of the tracer. A 24-hour urine collection demonstrated high normetanephrine levels of 24 µmol/L. These findings confirmed the diagnosis of PPS. CONCLUSIONS PPS is largely associated with HIF2A mutations. This article describes the case of a young PPS patient and highlights the importance of considering neoplasms in the differential diagnosis of hypertension in young patients. Further, it is crucial to conduct clinical investigations on young hypertensive patients to exclude underlying causes such as renal diseases, coarctation of the aorta, and neuroendocrine disorders.