Paraneoplastic production of granulocyte colony-stimulating factor in a bladder carcinoma.

We report the case of a 51-year-old female with poorly differentiated bladder carcinoma who presented with leukocytosis and hypercalcemia. Granulocyte colony-stimulating factor was noted to be twice the normal level. Paraneoplastic leukocytosis in bladder carcinoma is rare, is often associated with paraneoplastic hypercalcemia, and appears to represent a particularly aggressive form of the disease.