Background Case reports have documented carcinoid-like features in head and neck paragangliomas (HNPGLs), which, in addition to catecholamine storing granules, may also contain granules with serotonin. Serotonin is metabolized to 5-hydroxyindoleacetic acid (5-HIAA). Aim To assess the urinary excretion rates of 5-HIAA and catecholamines in HNPGL patients. Methods In 114 consecutive HNPGL patients, normetanephrine, metanephrine, norepinephrine, epinephrine, VMA, dopamine, 3-methoxytyramine and 5-HIAA excretion rates were measured in two 24-hour urinary samples. Increased excretion rates were defined as an increase of the average hormone excretion rate of 2 urine samples above the reference range. In all patients with catecholamine excess, intrathoracic and abdominal paragangliomas were excluded by 123I-MIBG scintigraphy, MRI and/or CT. Genetic screening for mutations in genes of the succinate dehydrogenase (SDH) family was performed. Results Mean urinary 5-HIAA excretion rate was 14±9 μmol/24 hours (reference range 10–44 μmol/24 hours). Urinary 5-HIAA excretion was slightly increased in only 1 patient (48 μmol/24 hours). None of the 50 patients (44%) with increased urinary excretion rates of catecholamines and/or their metabolites had elevated 5-HIAA excretion. Conclusion Urinary 5-HIAA excretion is within the normal reference range in almost all HNPGL patients. Therefore, this parameter has no clinical relevance in the routine clinical assessment of HNPGL patients.
Head and neck paragangliomas: Ten years of experience in a third health center. A cohort study
