Functioning paragangliomas are rare tumors originated from the neural crest cells that produce catecholamines. We present the case of an 11 year-old boy with severe arterial hypertension and a mass in the right cervical region. He presented increased levels of catecholamine and urinary fractions of epinephrine, 97.8 mg/24hs (Reference Values (RV)= 0.5 to 20); norepinephrine, 184.8 mg/24hs (RV= 15 to 80); dopamine, 513.5 mg/24hs (RV= 65 to 400); metanephrine, 0.08 mg/g creatinine (RV< 0.31); normetanephrine, 0.64 mg/g creatinine (RV< 0.43); vanilmandelic acid, 69.3 mmol/24hs (RV= 10 to 35). Scintigraphy with metaiodinebenzylguanidine (MIBG) showed increased uptake in the right cervical mass, which was confirmed by magnetic resonance image (MRI), which also showed a small mass in the left cervical region without increased MIBG uptake. A surgical procedure removed the right cervical lesion, normalizing blood pressure, catecholamine levels and urinary fractions. Immunohistochemistry was positive for neurospecific enolase, neurofilaments, cromogranin, somatostatin and serotonin that confirmed the diagnosis of a functioning paraganglioma and also identified the presence of anti-S100 protein, which is a predictor for good prognosis. The patient will be followed with periodic clinical and laboratory exams due to the mass in the left cervical region and to detect any possible relapse of the tumor. Despite the presence of good prognostic factors these tumors are considered potentially malignant.
Functioning paraganglioma; Extra-adrenal pheochromocytoma; Scintigraphy; Metaiodinebenzylguanidine; Catecholamine