We report on the case of a 67-year-old man with granulocyte colony-stimulating factor (G-CSF) producing anaplastic carcinoma of the pancreas. Preoperative routine tests revealed an elevated white blood cell (WBC) count of 25.2 G/l, consisting almost exclusively of neutrophilic granulocytes (23.31 G/l) with a predominance of segmented neutrophils (78% of all neutrophilic granulocytes), and elevated levels of C-reactive protein at 87 mg/l. Upon surgery, local tumour infiltration was more extensive than expected from preoperative imaging. However, no peritoneal dissemination was found and curative resection was attempted. Only seven days after the operation, signs of relapse were seen upon computed tomograpy. Histology revealed an undifferentiated anaplastic carcinoma, on the basis of a poorly differentiated ductal adenocarcinoma. Immunohistochemistry demonstrated G-CSF and G-CSF-Receptor expression in some CD68-positive syncytial macrophages. Granulocyte colony-stimulating factor (G-CSF) in serum was elevated at 5.6 pg/ml, which further raised to 43 pg/ml one week after FOLFIRINOX chemotherapy (oxaliplatin, irinotecan, 5-fluorouracil), while WBC decreased from 103.3 G/l to 59.3 G/l. Granulocyte macrophage-colony stimulating factor (GM-CSF) in serum was normal (<0.5 pg/ml). The patient died on postoperative day 34.
