Small cell carcinoma of the urinary bladder occurring after resection of transitional cell carcinoma

The patient was a 75-year-old man who initially presented with macrohematuria. Transurethral resection of bladder tumor (TURBT) was performed four times for superficial bladder tumor which revealed to be papillary transitional cell carcinoma (TCC) by histological examination. Follow-up cystoscopy two years and a half after initial TURBT showed a non-papillary tumor resembling submucosal tumor on the right wall of the urinary bladder. Transabdominal ultrasound, CT, and MRI showed a mass measuring about 2 cm on the right wall of the bladder. Transurethral biopsy of the mass was performed, and histological examination revealed small cell carcinoma. Lymph node swelling and distant metastasis were not detected by MRI, CT Radical cystectomy was performed. Histological and immunohistochemical examination of the cystectomy specimen revealed small cell carcinoma without TCC. One course of chemotherapy using carboplatin and etoposide was performed. At the 8 months after the cystectomy, the patient was healthy without evidence of recurrence or metastasis.