Background: Signet ring cell carcinoma is a very rare subtype of adenocarcinoma of the urinary bladder. Urine cytology is a useful method for screening and followup of urinary bladder carcinoma.
Case: A 43-year-old woman was referred for evaluation of painless hematuria. Laboratory evaluation showed anemia, hematuria and elevated tumor marker levels. Pelvic computed tomography (CT) demonstrated diffuse wall thickening, and the chest CT suggested metastatic lesions in the lung and hepatic dome. Abdominal CT, esophagogastroduodenoscopy and colonoscopy revealed no evidence of malignancy in the gastrointestinal tract. Cystoscopy revealed very large masses in the anterior and posterior wall of the bladder. Bladder washings, urine cytology and biopsy demonstrated characteristic signet ring cells without foci of urothelial carcinoma or other lesions. Three months later, ascitic fluid was obtained; the results showed signet ring cells identical to those seen in the urine specimen.
Conclusion: Signet ring cell carcinoma of the urinary bladder can be diagnosed by urinary cytology and confirmed by cystoscopic biopsy.