Papillary renal cell carcinoma with extensive paraaortic nodal metastasis mimicking malignant lymphoma.

A 52-year-old woman with abdominal distension underwent computed tomography (CT) that demonstrated extensive paraaortic lymphadenopathy and a right renal mass. Compared to the renal cortex, the lesions exhibited low signal intensity on T(1)- and T(2)-weighted images and high intensity on diffusion-weighted magnetic resonance (MR) images. We suspected malignant lymphoma and performed excisional biopsy, which revealed metastatic papillary renal cell carcinoma. Retrospectively, significantly reduced signal on in-phase chemical shift MR images compared to out-of-phase images suggested the presence of intratumoral hemosiderin, a characteristic finding of this entity.