Histological detection of minimal metastatic disease in inguinal non-sentinel lymph nodes in penile cancer.

The aim of this study was to detect lymphatic spread by serial step-section technique in non-sentinel lymph nodes (NSLNs), which were earlier assessed as negative by histological examination. Patients and Methods: Inguinal dissection specimens of 13 men with penile cancer were investigated. The LNs were sectioned at multiple levels (150 mu m-intervals) and then H&E- and immuno-stained for cytokeratin (Lu-5). Results: 196 LNs of 13 men were examined. In 2 out of 13 patients (15%) previously ranked as pNO, minimal lymph node involvement was detected by serial step sections and both immunohistochemistry and H&E staining. Both patients have had an unevenful follow-up of currently 62 and 16 months. Conclusion: Conventional histological examination of NSLNs fails to detect lymphatic spread in penile cancer. Step-section technique at 3 section levels, rather than immunohistochemistry, helps to safely detect minimal metastatic disease. The prognostic relevance is still unclear and has to be investigated in larger cohort studies.