Fig. 1.

A, The lesion shows infiltrating tubular structures containing eosinophilic, hyaline secretions (original magnification, × 200). B, The tubular structures are lined by cuboidal tumor cells demonstrating mild to moderate nuclear atypia (original magnification, × 400). C, The tumor cells show strong nuclear expression of the transcription factor PAX8 (immunohistochemistry for PAX8, original magnification × 200). D, There is nuclear and cytoplasmic expression of the tumor suppressor p16 (immunohistochemistry for p16, original magnification × 200).