A 30-year-old man presents to the clinic with recurrent symptoms of flushing, diarrhea, and weight loss. He cannot associate the symptoms with any particular activity, time of day or food ingestion. His past medical history is negative and he is not taking any prescription or recreational medications.On physical examination, his blood pressure is 126/74 mmHg, and the heart rate is 72/min and regular. His remaining physical examination is completely normal. Lab investigations reveal an elevated urinary 5-hydroxyindoleacetic acid (5-HIAA) Which of the following is the most likely diagnosis?
Carcinoid syndrome is characterized by increased levels of 5-hydroxyindolacetic acid. The syndrome occurs in relation to malignant tumors that have metastasized, usually with hepatic implants. Gastrointestinal carcinoids are most commonly found in the appendix. These are very slow growing, thus the 5-year survival rate is 99%. Many carcinoids are discovered as incidental findings on autopsy.
phenylketonuria
alkaptonuria
malignant melanoma
carcinoid syndrome
Endocrinology