Diagnostic Cytology
benign pelvic disease such as endometriosis.10 The procedure
involves the periumbilical insertion of a laparoscopic trocar
through which diagnostic material is procured by way of fine
needle, forceps cytologic brushing, or peritoneal lavage. Detailed
examination of the celomic cavity is facilitated by the stretching
of the peritoneal surfaces induced by gas insufflation, but effec-
tiveness is limited if adhesions are present as is common with
second-look procedures.
Implantable intraperitoneal chemotherapy port systems can
be used as sampling devices to collect washings for detection of
persistent intraperitoneal disease in ovarian carcinoma.11
Tumor implantation at the laparoscopy site is uncommon
but is more likely in patients with malignant effusion than in
those with low-grade tumors without ascites.12 Dissemination of
malignant cells via fallopian tube into the peritoneal cavity has
been reported following hysteroscopy for patients with endome-
trial carcinoma.13
The peritoneal cavity is normally completely lined by cuboidal
mesothelial cells overlying a subserosal stroma well supplied by
blood vessels and lymphatics. Detection of malignant tumor
cells in washings and free fluid depends on exfoliation of cells
and is influenced by such factors as extent of
peritoneal involve-
localization by
adhesion formation,
of tumor.
Spread of malignant cells tends to occur by way of the vascular
channels and lymphatics as well as across the peritoneal cavity,
where deposits tend to lodge in dependent areas such as the cul-
de-sac and paracolic gutters.
If there is no peritoneal involvement by tumor on gross
inspection, any
accumulated fluid
should be aspirated and sent
for cytologic evaluation. Otherwise
saline washings
are submitted
unfixed to the laboratory for processing as soon as possible; the
specimen is well mixed, and an aliquot is resuspended in cytol-
ogy fixative for preparation of cytocentrifuge or liquid-based
Cytologic smears
may also be prepared from sur-
faces such as the diaphragm, pelvic side wall, and solid viscera
using a wooden spatula or cytobrush and spray fixed in 95%
ethanol. The technique is convenient and cost effective and ena-
bles a relatively large surface area of peritoneum to be sampled.9
Cell block preparations are useful in the work-up of patients
with suspicious lesions in cytocentrifuge or liquid-based prepa-
rations as they may provide optimal assessments of preserved
architectural features and as a medium for multiple immunocy-
tochemical staining procedures.14
Peritoneal washings and brushings differ from effusions with
respect to cellularity and composition such as the presence of
detached sheets of mesothelial cells, which may give rise to prob-
lems in interpretation (Fig. 12.1). The diagnosis of metastatic
carcinoma in peritoneal washings, as with effusions, depends
on identification of single cells and papillary cell groups show-
ing obvious criteria for malignancy (Fig. 12.2).
Correlation with Histology
Review of histologic material from the primary tumor is very useful
in evaluating peritoneal washings with abnormal cells. Cytohis-
tologic correlation frequently assists in determining whether the
cells are morphologically compatible with the primary lesion.
Fig. 12.1 Flat sheet of mesothelial cells in mosaic pattern. Peritoneal
washing (Papanicolaou x MP).
Fig. 12.2 Serous papillary carcinoma. Papillary group and single cells
showing anisonucleosis and nucleoli. Fine-needle aspirate cul-de-sac
(Papanicolaou x HP).
Atypical Cells and Pitfalls for Diagnosis
Mesothelial cells are usually readily recognized as uniform-
appearing cells with bland nuclear chromatin,
a normal
nuclear-cytoplasmic (N/C) ratio, and sheet-like arrangements
with intercellular fenestrations. Difficulties may arise in the
interpretation of loose groups of cells with nuclear enlargement
and nucleoli (Fig. 12.3). Frequently there is evidence of a transi-
tion to normal-appearing mesothelial cells.
Cytologic atypia in mesothelial cells from peritoneal wash-
ings may be due to reactive changes associated with
cyst or
adnexal torsion, visceral adhesions, organizing hematoma
, and
inflammatory lesions such as
chronic salpingitis.15
Intraperitoneal chemotherapy may give rise to cytologic abnor-
malities that mimic malignancy.1
Peritoneal washings from pelvic
may show loose
clusters of atypical cells with decreased N/C ratios and promi-
nent nucleoli. Characteristic hemosiderin-laden macrophages
and spindle-shaped stromal cells may not always be present to
assist diagnosis15 (Fig. 12.4). Eosinophilic metaplastic change in
endometriosis may also present as a diagnostic pitfall. Although
well-differentiated endometrial adenocarcinoma has loose but
previous page 290 ComprehensiveCytopathology 1104p 2008 read online next page 292 ComprehensiveCytopathology 1104p 2008 read online Home Toggle text on/off