KRT20 and clear cell adenocarcinoma: Diagnosis of clear cell carcinoma was based on certain histological characteristics of the tumour and immunohistochemical analysis (PAS staining, keratins AE1/AE3, EMA, cytokeratin 7, cytokeratin 20, melanosomes, vimentin, Chromogranin, Synaptophysin, S-100, SMA).