[Transitional cell carcinoma of the renal pelvis in a woman discovered at childbirth].

We report a case of transitional cell carcinoma of a renal pelvis in a woman discovered after childbirth. A 38-year-old woman, who delivered an immature male infant in cesarean section 29 days prior to hospitalization, was admitted complaining of asymptomatic gross hematuria. Excretory urography and retrograde pyelography showed a filling defect of the right renal pelvis, Spontaneous urine cytology indicated class 5. Renal computed tomographic scan demonstrated a mass lesion in the right kidney. Right total nephroureterectomy and partial cystectomy was performed for diagnosis and treatment. Pathological diagnosis was papillary transitional cell carcinoma (grade 2). This is the first case of transitional cell carcinoma of the renal pelvis occurring in a childbearing woman in Japan.