With tissue, in obscure cases, it is possible to rely on, without limitation, the use of tumour markers (TTF1, PAX8, E-cadherin, p53, cytokeratin AE1/AE3) that allow ruling out tumours that require differential diagnosis, since they have a different prognosis and are treated in a different manner [21–23]. This evidence concerns the gene CDH1 and neoplasm.