All of the following statements about carcinoid syndrome are true except
Answer is D (Foregut carcinoids are usually argentaffin positive): Foregut tumors (carcinoids) have low serotonin levels and are argentaffin negative. Carcinoid Syndrome Typical Carcinoid Syndrome Elevated levels of plasma serotonin Elevated levels of urinary 5HIAA Atypical Carcinoid Syndrome Plasma serotonin levels are normal Plasma and urinary levels of 5HTP are increased (Urinary 5HIAA may he normal or mildly elevated) Typical carcinoid syndrome is charachteristic of Midgut carcinoids Midgut Carcinoids: Typical Carcinoid Syndrome Midgut tumors have high serotonin content are Argentaffin positives Most frequently cause a 'typical' carcinoid syndrome when they metastize. Release serotonin and tachykinins (neuropeptide K. substance K, substances P) Rarely secrete 5HTP or ACTH Metastatis to bone is uncommon (less common) Atypical carcinoid syndrome is charachteristic of foregut carcinoids Foregut Carcinoids: Atypical Carcinoid Syndrome Foregut tumor have low serotonin content, are argentaffin negative but argyrophillicQ Usually do not produce carcinoid syndrome but when they produce a carcinoid syndrome it is charachtristically usually an Atypical carcinoid syndrome Occasionally secrete ACTH or 5HTP May metastize to bone Are often multihormonal
Atypical carcinoid syndrome is usually produced by foregut carcinoids
Plasma serotonin levels are normal in Atypical carcinoid syndrome
Midgut carcinoids have high serotonin content
Foregut carcinoids are usually argentaffin positive