Leukocytosis due to markedly elevated granulocyte-colony stimulating factor levels in a patient with endometrial cancer: Case report and literature review.

•Granulocyte-colony stimulating factor (GCSF) secretion by gynecologic tumors is rare.•Elevations in serum GCSF can be seen in the absence of tumor GSCF secretion.•Extreme leukocytosis is associated with autocrine tumor growth and poor prognosis.