<prompt> 201. Sheetal, 39-yrs-old presents with chronic abdominal cramps, watery diarrhea, and periodic facial flushing. Examination reveals wheezing and a slightly enlarged liver. Work up reveals several masses within the liver and a large mass in the small intestine. Which of the following substances is likely to be elevated in her urine?5-HIAAAminolevulinic acid ALAFIGLUNorepinephrine  <response>: S-hydroxyindoleacetic acidS-HIAA The patient shows signs of the carcinoid syndrome, which include flushing, diarrhea, and bronchoconstriction. The syndrome results from elaboration of serotonin 5-hydroxytryptamine by a primary carcinoid tumor in the lungs or ovary or from hepatic metastases from a primary carcinoid tumor in the gastrointestinal tract. However, primary appendiceal carcinoid tumors, the most common gastrointestinal carcinoid tumors, very rarely metastasize and are viually always asymptomatic. Carcinoid tumors arise from cells of the neuroendocrine system, which, as pa of the, amine precursor uptake and decarboxylation APUD system, are capable of secreting many products, Grossly, carcinoid tumors, which tend to be multiple when they occur in the stomach or intestines, are characteristically solid and firm and have a yellow-tan appearance on sectioning, Histologically they are composed of nests of relatively bland-appearing monotonous cells. Diagnosis is based on finding increased urinary 5-hydroxyindoleacetic acid 5-HIAA excretion from metabolism of excess serotonin. In contrast, increased urinary levels of aminolevulinic acid ALA are seen with lead toxicity, increased N- formiminoglutamate FIGLU with folate deficiency, and increased normetanephrine or vanillylmandelic acid VMA with tumors of the adrenal medulla pheochromocytoma in adults and neuroblastoma in children. 