A Study to Detect Sentinel Lymph Node by Methylene Blue Dye and Histopathological Confirmation of Metastasis in Oral Squamous Cell Carcinoma Patient

Background: Oral Squamous Cell Carcinoma (OSCC) first metastasizes via lymphatic route and the first draining lymph node is Sentinel Lymph Node (SLN). SLN is identified by combine use of nuclear imaging and dye method, as nuclear imaging facility is expensive, not easily available and radioactive materials have more potential complications so dye alone can be an alternative.Aims: To assess the feasibility of using methylene blue dye (MBD) for detection of SLN in OSCC patient and using frozen section analysis to analyze metastatic status of SLN.Method: 20 patients with the histopathological diagnosis of OSCC, irrespective of stage underwent SLN identification by using a peritumoral injection of MBD. Surgery of neck was done first with reflection of subplatysmal flap to identify blue-stained node as SLN in the neck region and sent for frozen section analysis. Surgery was completed with primary resection and neck dissection. Histopathological analysis of SLN was done later.Results: SLN was identified in level Ib and II in 18 cases (identification rate=90%). The accuracy, sensitivity, specificity, PPV and NPV of SLN biopsy with frozen section analysis were 94%, 92.3%, 100%, 100%, 83.3% respectively.Conclusion: Methylene blue dye alone can be successfully used to detect sentinel lymph node in OSCC patient. SLN biopsy with frozen section analysis is sensitive enough to detect the metastatic status of regional lymph node