Fig. 1

Frozen sections of an O-CCC stained with H&E as diagnosed in the laboratory of pathology. a A field (original magnification ×10) containing abundant cells with clear cytoplasm, which are arranged around trabecular connective tissue (arrows). b (original magnification ×20) and c (original magnification ×40) denote the pathognomonic features of O-CCC, with hobnail cells (arrow in b), and large irregular cells with clear cytoplasm and eccentric prominent nuclei (arrowheads in b, c). The asterisk in c denotes a cell with clear cytoplasm, and excentric nucleus with a pseudo-inclusion. d An image of the tubulocystic aspect (arrows) of the clear carcinoma found in the omentum of the same patient