Abstract: Objective To explore the neck lump Fine Needle Aspiration cytology(Fine Needle from Cytology,FNAC)misdiagnosed reasons and improve FNAC diagnostic ability.Methods We analysized two misdiagnosed cases by FNAC of poor differentiated cervical lymph node metastatic cancer with Langhans-like giant cell reaction via clinical date,radiological examination,cytology characteristics,pathological changes and immunohistochemical staining results.Results The neck lump puncture from two patients showed that both were with lymphocyte given priority to a few epithelial cells and multinucleated giant cells,encountered with necrotic tissue and scattered oval cells as well as a few cells with large nuclei.The FNAC diagnosis was lymph node granuloma venereal change,and tend to be tuberculosis.By surgical specimens examination,several nodules,which completely coated with capsule and gray in cut,were seen with medium texture and focal necrosis.Histological features:Multifocal cancer nests were observed in lymph nodes,with small round and ellipse cells.Langhans giant cells was scattered or patchy around the nests.Multifocal coagulative necrosis were observed within the nests.Immunohistochemical staining:both cases were CKpan and p63 positive,while CK5/6 positive in one case and CK8/18 positive in the other.The pathological diagnosis was lymph node metastasis squamous cell carcinoma and poorly differentiated with Langhans giant cell response.Conclusion Misdiagnosis of lymph node granuloma venereal change or tuberculosis might happen when multinucleated giant cells and necrotic tissue were found in lymph node tissues with fine needle aspiration cytology.Carefully looking for tumor cells is very important.When necessary,lymph node biopsy and immunohistochemistry should be considered as the correct diagnosis.

Key words: Lymph node, Langhans giant cell samples, FNAC, Misdiagnosis, Diagnosis