Figure 12.

The threshold for the diagnosis of papillary carcinoma is highly variable and controversial. In this case, the nuclei show subtle atypia, including an irregularity of nuclear contour that makes the nuclei resemble “crumpled paper”. There are nuclear indentations and occasional grooves. These features are indicative of the diagnosis of papillary carcinoma and, in this case, the diagnosis was substantiated by immunoreactivity for ret in addition to molecular documentation of a ret/PTC1 gene rearrangement.