Granulocyte-colony stimulating factor producing rectal cancer

Background: Granulocyte-colony stimulating factor (G-CSF)-producing cancer has been reported to occur in various organs, especially the lung. However, G-CSF-producing colorectal cancer (CRC) has never been reported in the English literature. Case presentation: A 57-year-old man was admitted for the surgical removal of a rectal cancer. Some hepatic tumors in the liver were revealed concurrently, and their appearance suggested multiple liver metastases. Low anterior resection was performed. with the help of histopathological examination and immunohistochemical studies, we diagnosed this case to be an undifferentiated carcinoma of the rectum. After the operation, the white blood cell (WBC) count increased gradually to 81,000 cells/μL. Modified-FOLFOX6 therapy was initiated to treat the liver metastases, but there was no effect, and peritoneal dissemination had also occurred. The serum level of G-CSF was elevated to 840 pg/mL (normal range, <18.1 pg/mL). Furthermore, immunohistochemistry with a specific monoclonal antibody against G-CSF was positive; therefore, we diagnosed this tumor as a G-CSF-producing cancer. The patient died from rapid growth of the liver metastases and peritoneal dissemination 2 months after surgery. Conclusion: This is the first case of G-CSF-producing rectal cancer, and its prognosis was very poor.