Transdiaphragmatic extension of invasive thymoma.

The initial and follow-up computed tomographic (CT) examinations of 19 patients with surgically proven invasive thymoma were reviewed; 10 have been previously reported. Transdiaphragmatic extension of tumor was observed in six (31.5%) of the 19 patients. Sites of infradiaphragmatic invasion included the right lateral liver surface, posterior pararenal space, left paraaortic region, perigastric soft tissue, and spinal canal. In the patient with known or suspected invasive thymoma, transdiaphragmatic extension is a common occurrence that requires routine CT imaging of the upper abdomen to avoid underestimating the extent of disease.