A Metastatic Granulocyte Colony-Stimulating Factor Producing Sarcomatoid Carcinoma of the Lung Causing Jejunal Intussusception - Report of a Case

A 75-year-old man was referred to our hospital with intestinal obstruction caused by intussusception. Abdominal computed tomography (CT) revealed seven polypoid masses in the small intestine, while chest CT revealed a mass in the right lower lobe. Preoperative laboratory tests showed white blood cell (WBC) and neutrophil differential counts of 63,630/mm(3) and 95%, respectively. The serum granulocyte colony-stimulating factor (G-CSF) was 114 pg/mL, which was elevated (normal range, < 18.1 pg/mL). After resection of the small bowel, the WBC count decreased to 20,510/mm(3). The pathology showed a poorly differentiated carcinoma with sarcomatous components confirmed by positive immunostaining of cytokeratin (AE1/AE3) and vimentin in the small intestine. Furthermore, immunohistochemistry with specific monoclonal antibodies against G-CSF was positive. A lung biopsy revealed the same histological findings as the small intestine lesion. Therefore, the patient was diagnosed as having a G-CSF producing sarcomatoid carcinoma of the lung with metastasis to the small intestine.