Mediastinal carcinoid with an incomplete Sipple's syndrome.

A 60-year-old woman with a mediastinal carcinoid of probable thymic origin, widely metastatic, had associated parathyroid hyperplasia, medullary carcinoma of thyroid with amyloid stroma and an adrenal neuroma. This case demonstrated features of an incomplete Sipple's syndrome (MEA II). The relationship of these diverse tumors is consistent with the concept of the APUD system and neurocristopathies.