Clinically diagnosed primary transitional cell carcinoma of the colon: A case report.

INTRODUCTION: Most transitional cell carcinomas (TCCs) occur in the urinary tract. There are no reports of TCC originating in the colon. This report presents a very rare case of TCC that primarily occurred in the colon.

PRESENTATION OF CASE: A 78-year-old female presented with adenocarcinoma of the rectum and TCC of the ascending colon. She was screened for urologic and gynecologic carcinomas because the TCC was considered a metastatic lesion; however, cytodiagnosis of urine, the cervix and corpus uteri revealed no abnormal findings. An operation was performed, and histological examination revealed adenocarcinoma of the rectum and TCC of the ascending colon. Immunohistochemical stained specimens of the ascending colon revealed tumor cells of cytokeratin (CK) 7-/CK20+ pattern. Eleven months post-operation, a metastatic TCC was found in the liver. The patient was treated with chemotherapy; however, she died 19 months after the operation.

DISCUSSION: Our case was clinically considered that the TCC primarily occurred in the colon after analyzing the results of several examinations. Immunohistochemical staining of CK7 and CK20 expression pattern also suggested that the TCC of the ascending colon originated in the colon.

CONCLUSION: To the best of our knowledge, this is the first literature report of TCC that originated in the colon. TCC that primarily occurs in the colon may rapidly progress, as in the case presented. Therefore, it is necessary to establish more appropriate treatment for similar cases.