We report the case of a 67-year-old man with a left pharyngeal tumour, whose peripheral blood showed granulocytosis (white blood cell count, 58 300/μl) and a high serum granulocyte colony stimulating factor titre (184 pg/ml). The tumour showed pleomorphic proliferation of atypical spindle cells in a myxomatous stroma, revealing a sarcomatous pattern. The spindle-shaped neoplastic cells had irregularly shaped nuclei, a thick nuclear membrane, prominent eosinophilic nucleoli and abundant cytoplasm. They strongly expressed wide-spectrum keratin, cytokeratins (CAM5.2, MNF116), vimentin and vascular endothelial growth factor. A few neoplastic cells expressed granulocyte colony stimulating factor. A spindle cell carcinoma was diagnosed. This may be the first documented case of a granulocyte colony stimulating factor producing cancer arising in the pharynx. The patient died four months after the initial symptoms appeared.
