Intracaval and intracardiac extension of malignant thymoma: CT diagnosis.

There is disagreement about the ability of CT to detect isolated invasion of mediastinal vessels by malignant thymoma. Diagnosis usually depends on the absence of intact fat planes between the tumor mass and the adjacent vessel. We describe a rare case of CT demonstration of direct intraluminal invasion of a malignant thymoma into the superior vena cava and the right atrium.