Fibrosing mediastinitis: CT and MR findings

The aim of this study is to present the computed tomography (CT) and magnet ic resonance (MR) findings in three cases of fibrosing mediastinitis, proba bly secondary to tuberculosis. Two patients had diffuse involvement of the mediastinum and one patient presented with a posterior mediastinal mass. On CT, the patients with diffuse involvement showed infiltrating soft-tissue masses with multiple foci of dense calcifications. One of these lesions enh anced mildly with contrast and one did not enhance. On MR examination, diff use masses were of heterogeneous, intermediate and low signal on T1-weighte d images (n = 2) and were of homogeneous low signal (n = 1) or heterogeneou s (n = 1) signal intensity on T2-weighted images. After administration of G d-DTPA, these mediastinal masses showed heterogeneous enhancement. The post erior mediastinal mass showed homogeneous pronounced enhancement on CT and was homogeneous with intermediate T1 signal intensity and hypointense T2 si gnal intensity. The CT findings of an infiltrative or well-defined mediasti nal mass with scattered calcifications should suggest the diagnosis of fibr osing mediastinitis in the appropriate clinical setting. Although the appea rance of calcification on MR are not specific, this technique provides furt her information than CT especially in those cases in which the lesions appe ar noncalcified, because MR imaging revealed areas of low signal intensity characteristic of fibrous tissue.