Aggressive G-CSF-producing gastric cancer complicated by lung and brain abscesses, mimicking metastases.

A 57-year-old Japanese man had type II c gastric cancer with marked lymph node metastases associated with leukocytosis and elevated granulocyte colony-stimulating factor (G-CSF). Total gastrectomy and distal pancreatectomy with lymph node dissection were performed. Although the primary lesion was negative for G-CSF by histopathological immunostaining, a highly increased G-CSF m-RNA level, measured using reverse transcriptase-polymerase chain reaction in frozen sections, led to a diagnosis of G-CSF-producing gastric cancer. The leukocytes and G-CSF decreased immediately after surgery. He then had an intraabdominal recurrence, and was diagnosed with multiple tumors in his lung and brain, with abnormally elevated leukocytes and greatly increased G-CSF; he died 4 months after the surgery. Autopsy showed intraabdominal recurrence of cancer, with no metastases to the lung or brain, but with multiple brain and lung abscesses. We speculate that the excessively increased neutrophils induced by G-CSF infiltrated the lung and brain and formed abscesses, mimicking metastases.