Paraneoplastic granulocyte colony-stimulating factor secretion in soft tissue sarcoma mimicking myeloproliferative neoplasia: a case report.

Background: While paraneoplastic leukocytosis is a common phenomenon in solid tumors, extreme elevations of white blood counts (WBC) in the range of more than 100,000/μl are uncommon in patients with non-hematologic malignancies. Leukocytosis with mature neutrophils due to a granulocyte colony-stimulating factor (G-CSF) producing tumor is only seen on rare occasions.

Case Presentation: Massive neutrophil leukocytosis of approximately 100,000/μl was diagnosed in a 57-year-old Caucasian woman with metastatic undifferentiated endometrial sarcoma. A bone marrow trephine biopsy revealed massively increased granulopoiesis, but no evidence of monoclonal myeloproliferative disease. After the primary tumor had been resected, white blood count (WBC) plummeted and went back to nearly normal levels within one week. With progressive metastatic disease, granulocyte colony-stimulating factor (G-CSF) plasma levels were found to be increased by 10-fold. White blood count (WBC) strictly correlated with tumor burden and response to chemotherapy. In the final stage of treatment resistent disease, white blood count (WBC) approximated 300,000/μl.

Conclusion: We report on a granulocyte colony-stimulating factor (G-CSF) secreting undifferentiated endometrial sarcoma, which was associated with extreme neutrophil counts. White blood count (WBC) were closely correlated with tumor burden and associated with an aggressive clinical course. We suggest that paraneoplastic neutrophilia represents a poor prognostic sign in soft tissue sarcoma. In patients with similar constellations, antitumor therapy must not be delayed.