Cytologic features of sarcomatoid carcinoma of the urinary bladder: a case report.

Sarcomatoid carcinoma of the urinary bladder is a rare entity, whose histogenesis and biological behavior remain controversial. The cytological literature on sarcomatoid carcinoma in voided urine is very scarce. Clinically, the diagnosis of this tumor can be made by computed tomography (CT), magnetic resonance imaging (MRI), cytology, and biopsy material. In this study, cytology, histopathology, and radiological imaging were employed in order to reach a diagnosis of sarcomatoid carcinoma. CT imaging showed increased thickness of the bladder wall associated to a polypoid mass. MRI showed a 4-cm sized, broadly necked polypoid mass with calcification and ulceration at the right side of the bladder wall. T2W1 imaging showed low signal. Voided urinary cytology showed a scattered cellular presentation. The tumor cells had a high nucleo- cytoplasmic ratio, with elongated cytoplasm with faint with indistinct cytoplasm border. The nucleus was oval to round, with large and irregular nucleoli and irregular nuclear membrane. These tumor cells were positive for cytokeratin (CKAE1/AE3), vimentin, p53, carcinoembryonic antigen (CEA), α1-smooth muscle actin (SMA) by the immunoperoxidase staining. Histopathology showed spindle-shaped and clumped large tumor cells with abundant cytoplasm. Mitotic figures were frequently seen and varied from area to area (50% of the tumor cells were positive for MIB1).