Carcinoids associated with multiple endocrine neoplasia syndromes

Area of Science:

• Endocrinology
• Oncology
• Genetics

Background:

• Carcinoid tumors can be associated with Multiple Endocrine Neoplasia (MEN) types 1 and 2.
• Understanding the specific relationships between carcinoids and MEN subtypes is crucial for diagnosis and management.

Purpose of the Study:

• To investigate the clinical relationships between carcinoid tumors and MEN types 1 and 2.
• To identify the origins and characteristics of carcinoids in patients with MEN.

Main Methods:

• Review of nine patients with carcinoids and other endocrine tumors.
• Analysis of these nine patients combined with 56 previously reported cases from the literature.

Main Results:

• Most MEN-associated carcinoids (69%) originate from the foregut (thymus, bronchus, stomach, duodenum), unlike typical midgut/hindgut origins.
• Carcinoids are more frequently associated with MEN type 1 (59 patients) than MEN type 2 (6 patients).
• Thymic carcinoids in MEN are more common in males and often malignant (82%), while bronchial carcinoids are more common in females and typically benign (74%).
• Strong associations exist between thymic carcinoids and parathyroid tumors, and bronchial carcinoids and pituitary tumors.
• Hyperparathyroidism in carcinoid patients often involves parathyroid hyperplasia or multiple adenomas (82%).

Conclusions:

• Carcinoids can occur in association with both MEN type I and MEN type II.
• Foregut carcinoids warrant suspicion for underlying MEN.
• Clinical presentation of ectopic ACTH production in MEN patients can suggest bronchial carcinoids in females and thymic carcinoids in males.
• Routine thymectomy in MEN type I patients is recommended due to potential ectopic parathyroid glands and carcinoid development risk.