Alpha-fetoprotein (AFP) has been widely used as a
tumor marker for detecting
hepatocellular carcinoma and
yolk sac tumors. Recently, cases of
gastrointestinal cancer with elevated serum AFP levels have been reported. However, AFP-producing
colon cancer is considered rarer than other AFP-producing
gastrointestinal cancers. In this study, we report on a case of a 47-year-old woman who was diagnosed with
sigmoid colon cancer and underwent sigmoidectomy and
lymph node dissection. Postoperative
adjuvant chemotherapy (AC) was performed after the curative surgery. After the seventh course of AC, multiple liver masses and enlarged systemic lymph nodes were detected; these were later diagnosed as liver
metastases from
sigmoid colon cancer. Laboratory examination revealed high AFP levels (14,657.8 ng/mL). After confirming the recurrence, her condition worsened rapidly, and she eventually died 8 months after the operation. Autopsy and histopathological findings showed that the liver mass was positive for AFP staining, but the
sigmoid colon cancer tissue was not. We then determined that liver
metastases of the
colon cancer were more likely than germ cell
carcinoma according to the
clinical course and pathological findings. We assumed that
colon cancer cells can rapidly expand by dedifferentiation, and we diagnosed AFP-producing
colon cancer with liver
metastases. Despite curative surgery and AC for AFP-producing
colon cancer, the patient died of liver and systemic
lymph node metastases.