Malignant fibrous histiocytoma of soft tissue producing granulocyte colony-stimulating factor

We treated a rare case of malignant fibrous histiocytoma (MFH) of soft tissue that produced granulocyte colony-stimulating factor (G-CSF). The patient, an 80-year-old woman, was admitted because of a feeling of abdominal fullness and leg edema. An elastic, hard, tender tumor was palpated in the right thigh. Histopathological examinations of the tumor revealed atypical and prominent pleomorphic spindle-shaped cells with funicular arrangement, which were compatible with the diagnosis of MFH. Prominent leukocytosis (up to 84,300/microl), a high serum G-CSF concentration (82 pg/ml) and positive immunohistochemical staining of the tumor tissue for G-CSF indicated that G-CSF was produced by the MFH.