AIMS: The diagnosis of metastatic cutaneous melanoma (CM) on lymph node fine 
needle aspiration samples may be challenging and usually requires confirmation 
by immunocytochemistry. However, the cytological material could be too scant to 
order a broad panel of markers. In this case, the pathologist is forced to 
choose the most advantageous antibodies. The most commonly used melanocytic 
markers include S100, Melan-A, HMB45 and SOX10 but their diagnostic yield on 
cytological samples has been poorly studied. The current work aimed to evaluate 
the diagnostic performance of melanocytic markers when applied to cell blocks 
obtained from fine needle aspiration cytology (FNAC) of lymph node metastases 
from CM.
METHODS: S100, Melan-A, HMB45 and SOX10 were tested on cell block sections of 38 
lymphnode metastases from CM diagnosed by cytology. A combined score was built 
to evaluate each immunostaining, considering the intensity of the staining and 
the percentage of stained neoplastic cells.
RESULTS: S100 and SOX10 revealed a higher sensitivity (100%) than Melan-A and 
HMB45 for the diagnosis of metastatic CM. Furthermore, SOX10 emerged as the 
melanocytic marker with the best staining performance.
CONCLUSION: SOX10 has a 100% detection rate and the most easily interpretable 
staining pattern compared with other melanocytic markers. Therefore, it is 
strongly recommended that SOX10 is included in the minimal immunocytochemical 
panel for the diagnostic evaluation of lymph node FNAC in patients with 
suspected CM metastasis.