Magnetic resonance imaging findings in pulmonary Kaposi's sarcoma: a series of 10 cases

Since chest X-ray and CT scan features of Kaposi's sarcoma (KS) are nonspecific, we wanted to test the hypothesis that the histological components of this tumour and/or the associated haemorrhagic component, may result in a characteristic signal pattern on magnetic resonance imaging (MRI). Thoracic MRI was performed in a prospective manner in ten patients with acquired immune deficiency syndrome (AIDS) and pulmonary KS. MRI examinations (1.5 Tesla) included Spin-echo T1 (SE-T1), before and after gadolinium injection, as well as T2-weighted sequences (SE-T2). For each sequence the signal intensity of lesions was measured and compared with each other as well as with the signal intensity of muscle. Results were compared to the hemosiderin content of macrophages in the bronchoalveolar lavage (BAL) in all patients and with histological findings in three. The results were compared to values obtained in a control group of seven patients with pneumocystis carinii pneumonia. SE-T1 showed focally increased signal intensity in the pulmonary parenchyma (n = 5). Signal enhancement in parenchymal lesions (n = 10) and along peribronchovascular trees (n = 5) was observed after gadolinium injection. The second echo of SE-T2 showed a markedly reduced signal intensity in pathologic areas (n = 10). This last finding was not observed in the control group. In conclusion, we have identified a pattern of MRI signal abnormalities suggestive of Kaposi's sarcoma. The MRI signal intensity of KS lesions may be related to the angiomatous and fibrous components of the tumour.(ABSTRACT TRUNCATED AT 250 WORDS)