Urinary 5-HIAA excretion is not increased in patients with head and neck paragangliomas.
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).


OBJECTIVE
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.


CONCLUSIONS
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.
Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden - the Netherlands. L.T.van_Hulsteijn@lumc.nl
Leonie T
LT
van Hulsteijn
Nicolette
N
van Duinen
Johannes A
JA
Romijn
Johannes W A
JW
Smit
Eleonora P M
EP
Corssmit
D014408:Biomarkers, Tumor / Q000652:urine*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D006258:Head and Neck Neoplasms / Q000175:diagnosis / Q000652:urine*; D006801:Humans; D006897:Hydroxyindoleacetic Acid / Q000652:urine*; D010235:Paraganglioma / Q000175:diagnosis / Q000652:urine*
D014408:Biomarkers, Tumor; D006897:Hydroxyindoleacetic Acid