KRT20 and neoplasm: On immunohistochemistry, the tumour cells were diffusely and firmly positive for thyroid transcription factor 1 (TTF1), B cell leukemia/ lymphoma 2 (BCL2), tumour protein 53 (TP53)-70% (+3), focally and weakly positive for thyroglobulin (TG) and Cytokeratin 7 (CK7), while negative for calcitonin, carcinoembryogenic antigen (CEA), cytokeratin 20 (CK20), and cyclin D1.