The Usefulness of Cytokeratin Immunohistochemistry in Detection ofLymph Node Micrometastases in Neck Dissection Specimens

Cervical lymph node metastasis in head and neck cancer patients is one of the most important prognostic factors. The previous studies have shown that the detection of occult micrometastases using immunohistochemical method is superior compared to the routine hematoxylin-eosin stain. The aim of this study was to document the rate of missed occult micrometastases on routine hematoxylin-eosin stain. Materials and Method：Sixty-nine tumors from the patients with squamous cell carcinoma of the head and neck were included. Immunohisto-chemical staining was performed using Pan-cytokeratin AE1/AE3 antibody. The number of lymph nodes examined was 1710 (mean per patient：24.8；range： one to 66). Results：Of 69 tumors studied, 14 lymph nodes had occult metastases detected by the immunohistochemical method. On review by pathologist, the lymph node metastases were confirmed in 4 of 14 lymph nodes, whereas even on hematoxylin-eosin stain. Hematoxylin-eosin stain was not sufficient to detect occult micrometastases in 10. Conclusion：Because immuno-histochemical method enhanced the detection rate of occult micrometastases in cervical lymph nodes of head and neck squamous cell carcinoma patients, it is recommended for routine diagnostic use in every patient, in whom the lymph nodes show negative for metastasis on routine hematoxylin-eosin stain. (Korean J Otolaryngol 2002;45:495-500)