A potential prognostic marker in primitive lung neuroendocrine tumor: A case report.

BACKGROUND The diagnosis and monitoring of primitive lung neuroendocrine tumors (lung pNETs) are usually performed by the measurement of serum chromogranin A (CgA) and urinary 5-hydroxyindolacetic acid (5-HIAA) levels. However, imaging techniques are necessary due to the poor diagnostic efficiency of the laboratory tests. METHODS A total-body computed tomography and bone scintigraphy scans showed multiple hepatic and bone metastases of a 55-year-old man affected by well-differentiated lung pNETs without severe initial symptoms. After diagnosis, he started therapy and was monitored with serum, urinary markers, and imaging techniques. RESULTS During follow-up, the urinary 5-HIAA levels did not significantly increase, while serum CgA and urinary para-hydroxyphenylacetic acid (pHPAA) levels (urinary organic acid physiologically present in the urines of healthy subjects) showed significant increases related to worsening clinical condition. CONCLUSIONS The early increase in urinary pHPAA levels-usually not dosed in pNET patient monitoring-could be a promising prognostic marker.