Immunohistochemical staining with cytokeratin combining semi-serial sections for detection of cervical lymph node metastases of oral squamous cell carcinoma

Objectives Lymphatic metastatic characteristics of oral squamous cell carcinoma are not fully understood, for instance, skip metastasis is still controversial. The purposes of the present study was to explore the accuracy and applicability of immunohistochemical stain with cytokeratin combining semi-serial sections for detection of cervical lymph node metastasis of oral squamous cell carcinoma. Methods Regional lymph nodes (N = 1638) were obtained from 26 patients with primary oral squamous cell carcinoma who underwent five level neck dissections. Semi-serial sections at an interval of 0.5 mm was performed for each lymph node and cross-detected by immunohistochemical staining with cytokeratin and traditional hematoxylin–eosin staining (H–E) and their accuracies were compared. Results Of 26 patients, 21 were detected having lymphatic metastasis by H–E staining and 26 by immunohistochemical detection; Of 1638 lymph nodes, 52 metastatic lymph nodes were detected by H–E staining while 162 by immunohistochemical detection. One case with cancer of the mouth floor being defined having skip metastasis was proved having no skip metastasis by the immunohistochemical detection. Conclusions The immunohistochemical detection method with semi-serial sections has higher accuracy than the traditional H–E staining and its application may present a need to re-evaluate the neck metastatic patterns of oral squamous cell carcinoma.