The pap smear contains small clusters of glandular cells having occasionally vacuolated cytoplasm. Some papillary structures are noted. The cells have slightly atypical nuclei with irregular contours and focally prominent nucleoli. The groupings occur in small sheets and tighter 3-dimensional clusters.
Some mucin is noted within the glandular lumens.
In the papillary regions, there are delicate long fibrovascular cores with crowded pseudostratified nuclei and frequent mitotic figures. No solid non-glandular areas are noted. No squamous differentiation is noted. Endometrial adenocarcinoma is the most common invasive gynecologic malignancy. The incidence has peaked in the mid-1970's and fallen again to levels reflective of the 1950's.