Unusual sites of colorectal cancer metastasis.

We present 2 separate cases of adenocarcinoma of the colon with metastasis to the chin and the bladder, both of which are unusual sites of colorectal cancer metastasis. Patient 1 is a 77-year-old man who was diagnosed with adenocarcinoma of the colon, American Joint Committee on Cancer (AJCC) T4 N0 M0 (stage II), and underwent a right hemicolectomy. Fourteen months later he developed a firm 2.5-cm mass involving the chin. Excisional biopsy revealed moderately differentiated adenocarcinoma, consistent with the known colon primary tumor. Patient 2 is a 75-year-old man who was diagnosed with AJCC T3 N1 M0 (stage III) adenocarcinoma of the colon and underwent sigmoid colectomy. Ten years later, he was found to have transitional cell carcinoma involving retroperitoneal nodes with no identifiable bladder or ureteral primary, for which he received chemotherapy. Eighteen months following this diagnosis, he developed hematuria and was found to have metastatic colon adenocarcinoma involving the bladder. Details of both patient cases are presented here.