Placental examination: take four full-thickness sections
of placental disc, one from each quadrant. These sections
are meant to represent the placenta, not the uteroplacental
interface. Any focal lesions, such as infarct
or hematoma, should be represented. Retroplacental
hemorrhage should be represented in additional cassettes
to evaluate for abruption. Take one cassette
representing cord and one cassette representing the free
membranes and underlying chorion leave, decidua vera
and non-implantation myometrium to the serosa (this is
most often the posterior wall of the uterus).
2. Cervix/LUS: take two sections of cervix or LUS to
represent placenta previa and ectocervix (if present).
Ectocervical mucosa may be difficult to identify on
gross exam, so take sections on the lip of the gaping
opening at the base of the uterus.
3. Invasive interface: the area of accreta and myometrial
wall invasion was documented in cross sectional
photographs, but the submitted sections should map
and confirmed this histologically. It is these sections
which allow the pathologists to make the definitive
diagnosis of accreta, increta, or percreta. For example,
if villi are seen adjacent to adipocytes, the diagnosis of
placenta percreta is confirmed. Areas of shallow and
deep invasion should be represented as these show the
relationship to prior c-section scar and allow quantifi-
cation of other features of abnormal implantation such
as venous invasion, infiltrating trophoblast, inflammation,
and trophoblast invasion of subserosal uterine
arterioles. Take sections of areas showing abrupt
transition from thick to thin myometrium rather than
random sections from thinned regions of the lower
uterine segment. This approach is much more likely to
pick up the c-section scar.
4. The location of the sections should be indicated on the
specimen photographs. Some may choose to take an
additional mapping photograph with the cassettes laid
over the slices to indicate areas sampled.