Carcinosarcoma of the gallbladder producing alpha-fetoprotein and manifesting as leukocytosis with elevated serum granulocyte colony-stimulating factor: report of a case.

A 69-year-old man was referred to our hospital for investigation of leukocytosis and a persistent fever of 38 degrees C, but we could find no evidence of a specific infection. The leukocyte count was 18,000/mm(3), and the serum granulocyte colony-stimulating factor (G-CSF) and alpha-fetoprotein (AFP) levels were both elevated, at 66.3 pg/ml and 1,495 ng/ml, respectively. Computed tomography (CT) showed a gallbladder tumor and we performed extended cholecystectomy. Postoperatively, the fever subsided and the leukocyte count, serum G-CSF and AFP level normalized. Histologically, the tumor was a carcinosarcoma of the gallbladder. Immunohistochemical staining of the tumor cells was positive for AFP, but negative for G-CSF. This is the first report of a carcinosarcoma of the gallbladder producing AFP. The laboratory findings and clinical course strongly suggested that the tumor produced not only AFP, but also G-CSF.