Aggressive Recurrent Pancreatic Cancer Producing Granulocyte Colony-Stimulating Factor.

Granulocyte colony-stimulating factor (G-CSF) is a glycoprotein which stimulates the proliferation, differentiation, and functional activation of myeloid hematopoietic cells. G-CSF-producing pancreatic cancer is rare and its prognosis is strikingly poor. A 69-year-old woman with well-to-moderately differentiated ductal adenocarcinoma (pT3N0M0, stage IIA) underwent distal pancreatectomy and splenectomy. Postoperative adjuvant chemotherapy with S-1 was administered for 6 months. Eleven months after surgery, periodic blood examination revealed remarkable leukocytosis (19,120/µL) without fever, which worsened 3 weeks later (36,160/µL). Furthermore, laboratory data showed elevation of the fibrin degradation product-D dimer and that the G-CSF level was high (406 pg/mL), as well as thrombopenia. Multiple liver and lung metastases were detected by contrast-enhanced computed tomography (CT). The patient was treated with gemcitabine plus nab-paclitaxel, and heparin, thrombomodulin alfa, and platelet transfusion were administered concurrently. Leukocytosis and thrombopenia were alleviated after 1 course of chemotherapy. However, remarkable leukocytosis (53,480/µL) recurred on day 1 of the third course of chemotherapy. Contrast-enhanced CT showed a significantly increased number of liver metastases and lung metastases. The patient chose not to receive second-line chemotherapy and died 1 month later at the affiliated hospital. Pancreatic cancer producing G-CSF shows very aggressive behavior. Leukocytosis without infection during routine observation should be considered as a warning of a rapidly growing recurrence.