Micropapillary variant of invasive urothelial carcinoma is a rare and agressive tumor of the urinary bladder. Its prompt diagnosis in biopsies may contribute to patient survival. A 49 years of male patient admitted to hospital with hematuria in 1998 and diagnosed as high grade urothelial tumor had been treated by transurethral resection of tumor after cystoscopic evaluation. The tumor recurred several times after transurethral resection (TUR) and maintenance intravesical BCG treatment. Despite treatment, tumor was recurred and diagnosed as invasive carcinoma by histopathological examination of transurethral resection of tumor. Consequently, the patient underwent radical cycstoprostatectomy. In gross examination of the bladder, an ulcerated lesion occupying left lateral wall, trigon and partly right lateral wall was seen. Adjacent to ulcerated area, there was a polyp. Histological examination of the samples from the tumor confirmed the initial pathologic diagnosis of urothelial carcinoma. Histologically tumor mostly composed of micropapillary structures. In some areas, adenocarcinoma-like pattern was recognizable. A metastatic lymph node showed micropapillary pattern involvement. The expression of cytokeratin 7 and 20, epithelial membrane antigen (EMA), Leu M1 and carcinoembrionic antigen (CEA) were investigated immunohistochemically. Immunostaining pattern was comparatively examined in two different areas and metastatic lymph node. EMA and cytokeratin 7 expressions was consistently positive in these areas. Cytokeratin 20 was negative. CEA was focally positive in the tumor but negative in the metastatic lymph node. Leu M1 expression was focally positive in micropapillary area in both bladder and metastatic lymph node, but adenocarcinoma-like patern was negative. Micropapillary variant of invasive urotelial carcinoma is highly agressive and rather rare. Although the morphologic features of the cells may appear as low grade origin, the tumor has a an aggressive course. Early recognition of this variant may contribute to patient’s survival. Histological examination and immunostaining pattern may be helpful in diagnosis.

Keywords: Bladder, carcinoma, micropapillary