Abstract
We reported a very rare case of tiny carcinoid arising in an epidermoid cyst of the thymus. The patient was a 50-year-old female who had anterior chest compression. Chest X-ray showed a tumor shadow in the right upper mediastinum. Chest CT and MRI revealed a substantial tumor 2.0×2.0cm in size located in the thymus, and so we suspected thymoma and performed thymectomy. Macroscopic findings of the resected specimen showed a tumor 25×24×20 mm in size in the right upper portion of the thymus. Cut surface of the resected specimen showed a simple cyst filled with keratin. Microscopic findings showed a tiny typical carcinoid arising in an epidermoid cyst of the thymus. Immunohistochemical studies showed positive staining of carcinoid tumor cells with chromogranin and neuron-specific enolase. The postoperative course was uneventful and there are no findings of tumor reccurence 16 months after operation.
