 The surgeon then removes these lymph nodes and sends them to a pathologist for rapid examination under a microscope to look for the presence of cancer.A frozen section procedure is commonly employed (which takes less than 20 minutes), so if neoplasia is detected in the lymph node a further lymph node dissection may be performed.With malignant melanoma, many pathologists eschew frozen sections for more accurate "permanent" specimen preparation due to the increased instances of false-negative with melanocytic staining.