Histologic features of digital papillary adenocarcinoma

(A) Digital papillary adenocarcinomas have a multi-nodular growth pattern with ductal differentiation. Cystically-dilated areas are frequently present (H&E 40x).
(B) Papillary projections into dilated ductal spaces are a characteristic finding. This example shows numerous mitotic figures, crowding of tumor nuclei, and prominent cytologic atypia (H&E 200x).