Mediastinal teratoma: CT differentiation of ruptured and unruptured tumors

OBJECTIVE. The purpose of this study was to differentiate ruptured from unruptured mediastinal teratomas using CT. MATERIALS AND METHODS. CT findings in 17 cases of surgically resected mediastinal teratomas were reviewed retrospectively. Preoperative rupture was found in seven patients during surgery, We compared the clinical symptoms and CT findings of ruptured tumors with those of unruptured tumors. On CT, we evaluated size, wall thickness, location of the mass, presence or absence of internal septation, homogeneity of the internal components of each compartment, calcification or fat within the mass, and ancillary findings in adjacent structures. RESULTS. Severe symptoms (chest pain or hemoptysis) were more commonly found in ruptured (71%) than in unruptured tumors. All ruptured mediastinal teratomas had a tendency to display inhomogeneity of the internal components, whereas 90% of unruptured masses showed homogeneous densities of internal components in each compartment of the mass. Ancillary CT findings in ruptured tumors included fat-containing masses in adjacent lung parenchyma in two patients, consolidation or atelectasis in the adjacent lung in three patients, pericardial effusion in one patient, and pleural effusion in four patients. CONCLUSION. In cases of mediastinal teratoma, CT findings of inhomogeneity of the internal components and changes in the adjacent lung parenchyma, pleura, or pericardium can be used as signs of tumor rupture.