Malignant thymoma with direct invasion into the peritoneal cavity: report of a case.

Extrathoracic invasions or metastases from thymomas are extremely rare. We describe herein the case of a patient with malignant thymoma which recurred three times during an 8-year period and invaded directly into the peritoneal cavity, involving the gastrointestinal tract. The huge thymoma was completely resected, along with the fornix of the stomach, the transverse colon, and the 8th, 9th, and 10th ribs. Careful observation and multidisciplinary treatment against recurrent thymoma will be requisite for this patient, even though the tumor has been completely resected.