Malignant carcinoid syndrome: two case reports.

The malignant carcinoid syndrome (MCS) is a rare complication of malignant carcinoid neoplasms, fewer than 200 cases having been reported since its description by Thorson in 1954. Its signs and symptoms vary with the site of the primary neoplasm, and MCS is now recognized as one member of the large family of endocrine tumors--APUDOMAS). Although MCS remains uniformly fatal, significant palliation can be provided some patients with current surgical and chemotherapeutic management. All signs and symptoms in MCS, except evidence of the destruction of the tricuspid and pulmonic valves, can be reproduced experimentally. The factor causing this lethal complication has not been identified. Two previously unreported cases of MCS, each from the gastrointestinal (GI) tract, are presented. This brings the world's total report cases to approximately 210.