Fig. 2.

Variants of papillary thyroid carcinoma. a Oncocytic variant with large cells showing abundant eosinophilic cytoplasm and nuclear features of papillary thyroid carcinoma. b Solid variant with sheets of tumor cells with abundant cytoplasm and nuclear features of papillary thyroid carcinoma including cytoplasmic invagination into nuclei. c Diffuse sclerosing variant showing abundant psammoma bodies, and squamoid changes in the tumor cells. A prominent lymphocytic infiltrate is present in the background. d Papillary thyroid carcinoma with prominent hobnail features. The tumor consists of hobnail cells with loss of polarity and high grade cytologic features including prominent nucleoli and increased mitotic activity