Xanthogranulomatous cystitis imitating bladder neoplasm: a case report and review of literature.

Xanthogranulomatous cystitis is a rare, benign chronic inflammatory disorder with unclear etiology. Since its similar features to bladder neoplasm, it is extremely easy to be mistaken for malignant tumor. We herein reported a case of xanthogranulomatous cystitis in a 54-year-old male who presented with low abdominal pain and painless, total macrohematuria. Microscopy showed proliferation of large foam histiocytes which expressed CD68 and vimentin. Ki-67 showed a lower proliferation index (< 10%). Histopathology and immunohistochemical findings confirmed the diagnosis. This case highlighted the significance of recognizing this unusual lesion and differentiating it from its histological mimics by immunohistochemical staining.