Granulocyte-colony stimulating factor-producing pancreatic cancer: report of a case.

A 74-year-old man was hospitalized for the investigation of fever and severe general fatigue. Laboratory examinations revealed severe leukocytosis, with a leukocyte count of 29 500/mm(3). Computed tomography, ultrasonography, and endoscopic retrograde cholangiopancreatography showed a pancreatic tumor with a diameter of 70 mm. We performed distal pancreatectomy with splenectomy and gastrectomy because there was invasion of the posterior wall of the stomach. The leukocyte count decreased to 16 900/mm(3) immediately following the operation, but it began to increase again a week later, ultimately reaching 213 000/mm(3). We measured the serum granulocyte-colony stimulating factor (G-CSF) concentration and the G-CSF expressions in the resected specimens with immunohistochemistry, the findings of which confirmed the diagnosis of G-CSF-producing pancreatic cancer. G-CSF-producing tumors are considered to be in a category of rare malignant diseases originating in various organs, which carry a poor prognosis. However, G-CSF-producing pancreatic cancer is extremely rare. On postoperative day (POD) 35, an intraabdominal recurrence was detected with marked leukocytosis, and on POD 42 the patient died without receiving postoperative cancer therapy.