A case of polypoid and papillary cystitis mimicking an advanced bladder carcinoma with invasion of perivesical fat.

A rare case of polypoid and papillary cystitis without a history of catheterization is reported. A 69-year-old man was admitted to our hospital because of pain during urination and gross hematuria. The cystscopic and imaging findings including ultrasound, CT, and MR image showed an irregular wall thickening and stranding in the perivesical fat, which indicated an advanced bladder carcinoma, but histopathological findings obtained by transurethral resection revealed polypoid and papillary cystitis. Such benign lesions need to be discussed in the differential diagnosis of patients with bladder tumor to avoid excessive resection.