Abnormal 67Ga uptake in a fibrosarcoma of the pericardium with malignant transformation.

A 31-year-old woman presented with general malaise, back pain, and edema of the lower extremities. A chest X-ray film showed an enlarged cardiac shadow and clear lung fields. A pericardial lesion with decreased activity on blood pool imaging and increased uptake on gallium citrate imaging displaced the heart upwards and to the left. The pericardial mass showed an inhomogeneous signal intensity on MRI and was large enough to obstruct the venous return by compressing the heart. At operation, the mass was found to originate from the pericardium and was histologically identified as a malignant fibrosarcoma. Twelve years previously, the patient had undergone an operation for the removal of a pericardial tumor which was histologically identified as a benign hemangioma. In view of the rarity of pericardial tumors, the present tumor is suspected to have undergone a transformation from benign hemangioma to malignant fibrosarcoma.