The presence of endocervical adenocarcinoma in situ (AIS) can be suspected when hyperchromatic crowded groups (HCGs) are identified in a cervical/endocervical cytology preparation.
Low power features of hyperchromatic crowded groups (HCGs):
(1) groups of endocervical cells forming complex branched glands, rosettes, acini, short strips or small sheets
(2) crowded, overlapping and hyperchromatic nuclei often forming palisades (feathering) around the periphery of the cellular groups
(3) clean background
Cellular features of cells in HCGs:
(1) scant cytoplasm
(2) cigar-shaped nuclei with coarse nuclear chromatin
(3) mitotic activity
Differential diagnosis:
(1) pseudo-feathering from cytoplasmic protrusions rather than nuclear crowding
