[Case of inflammatory lesion in urinary bladder showing high signal intensity on diffusion-weighted MRI: correlation with histopathological finding].

A 66-year-old woman was referred to our department for thickening bladder wall incidentally found during postoperative follow-up of transverse colon cancer. Cystoscopy showed edematous tumor with a diameter of 5 cm on the right wall. Deep portion of the tumor showed high intensity on diffusion-weighted magnetic resonance imaging (DW-MRI). Transurethral resection and transvaginal needle biopsy was performed, and pathological examination revealed granulation tissues mainly consisted of inflammatory cells and fibrosis. DW-MRI is a functional imaging constructed by quantifying the diffusion of water molecules. Recently, the feasibility of this imaging in the diagnosis of bladder cancer has been reported. However, we should keep in mind that granulation tissues consisted of inflammatory cells and fibrosis is also possible to be positive for DW-MRI.