Late recurrence of cancer stem cell-positive colorectal cancer liver metastases after 15 years

No cases of late recurrence of colorectal cancer liver metastasis (CRLM) over 10 years have been reported in the literature. A 72-year-old woman had a surgical history of sigmoid colectomy and partial hepatic resections for sigmoid colon cancer and multiple liver metastases 15 years previously. The patient had been postoperatively treated with chemotherapy for 6 months and was observed regularly with no recurrence. Computed tomography (CT) performed due to high carcinoembryonic antigen (CEA) revealed a tumor of 70 mm in diameter at the anterior segment of the liver and a 6-mm nodule at the left lateral segment. There was no other malignant finding. We performed central bisegmentectomy and partial resection of the liver. Pathological findings showed the tumors to be well to moderately differentiated adenocarcinoma, and positive cytokeratin 20 (CK20) and caudal-type homeobox transcription factor 2 (CDX2) expression with negative expression of cytokeratin 7 (CK7). In addition, the tumors showed cluster of differentiation 44 (CD44) and 133 (CD133) positive signified cancer stem cell immunohistochemically. The postoperative diagnosis was recurrence of hepatic metastasis of sigmoid colon cancer. We report a rare case of late recurrence of CRLM more than 15 years after the primary diagnosis.