Mediastinal paraganglioma.

We present a case of mediastinal paraganglioma with radiologic-pathologic correlation. A 48-year-old woman was found incidentally to have a middle mediastinal mass on CT. The mass showed iso-signal intensity compared to that of muscle on T1-weighted images and high signal intensity on T2-weighted images. The lesion showed intermediate intensity on diffusion-weighted imaging, and its apparent diffusion coefficient was 1.72 × 10(-3) mm(2)/s. A contrast-enhanced dynamic study revealed a rapid peak and washout enhancement pattern. (18)F-FDG-PET revealed abnormal uptake in the mediastinal tumor with a maximal standardized uptake value of 7.88. (123)I-meta-iodobenzylguanidine scintigraphy also showed abnormal uptake in the tumor. These findings corresponded to the hypervascularity, rich stroma, low nuclear/cytoplasmic ratio, and nest-forming proliferation of tumor cells with positive neuroendocrine markers.