14
Alimentary Tract (Esophagus, Stomach, Small Intestine, colon, Rectum, Anus, Biliary Tract)
to play a central carcinogenic role in the much less common
squamous cell carcinomas primary in the rectum.176
Recognition of HPV-related changes in anal cytology is based
on the cytomorphologic criteria for squamous cell lesions of the
cervix as their diagnostic criteria.177-183 Figure 14.30 shows an
anal brushing diagnostic of squamous cell carcinoma. The cells
show malignant criteria including high N/C ratios and both
keratinized and more poorly differentiated malignant squa-
mous cells present. Some workers have found that koilocytes
occur less frequently than in the cervix despite the presence of
HPV. Depending on criteria for the diagnosis of an abnormal
smear, anal cytology has rather low levels of diagnostic sensi-
tivity or specificity. Sherman and colleagues have demonstrated
that automated LBPs enhance the diagnostic yield for anal dys-
plasia.184 A recent study suggests that reflex HPV DNA testing
would be helpful in patients diagnosed with atypical squamous
cells of undetermined significance (ASC-US). Patients diag-
nosed with low-grade squamous intraepithelial lesions (LGSIL)
or above should go directly to anoscopic biopsy.185 Additional
studies for determining which cytomorphologic features can
best predict the underlying histologic abnormality are probably
indicated.186
Biliary Tract
Normal Histology and cytology
The right and left hepatic ducts fuse to form the common hepatic
duct, which is jointed by the cystic duct, forming the common
bile duct. The entire biliary duct system is lined by a simple tall
columnar epithelium with small basally oriented nuclei. The
walls of the ducts include mucus-producing glandular struc-
tures. The common bile duct enters the duodenum through the
papilla of Vater. In most individuals, the common bile duct is
joined by the main pancreatic duct just before entering the duo-
denum. This pancreatic duct is lined by a very similar-appearing
columnar epithelial layer.
In brushing specimens, ductal epithelium presents in large
flat monolayers with preservation of cohesion and polar-
ity. These epithelial cells possess a single small centrally posi-
tioned nucleus, dense cytoplasm, and well-defined cell borders.
Fig. 14.30 Anal squamous cell carcinoma. Malignant keratinized cells
with high N/C ratios are associated with more poorly differentiated cells with
dense cyanophilic cytoplasm (Papanicolaou x HP).
The columnar configuration can be recognized in the cells at
the edges of aggregates. Chromatin is finely granular and pale
stained, and nucleoli are inconspicuous (Fig. 14.31). Constitu-
ents of bile may be seen in the smear background as amorphous
or crystalline material that, with the Papanicolaou stain, may
appear bright yellow.
Adenocarcinoma
The vast majority of malignant neoplasms involving the extra-
hepatic biliary ductal system are adenocarcinomas. Fortunately,
these tumors are quite uncommon. A well-recognized but infre-
quent predisposing condition is ulcerative colitis. Infection by
liver flukes may predispose to this malignancy in Asia. Unlike in
carcinoma of the gallbladder, men are affected slightly more fre-
quently. Although adenocarcinomas may occur anywhere along
the length of the ductal system, they are most frequent in the
distal portion. In most patients, symptoms are directly related
to obstruction of the ductal system, namely, obstructive jaun-
dice that is usually painless and pruritus. Occasionally, fever and
abdominal pain are the major manifestations and result from
ascending bacterial cholangitis. Most adenocarcinomas are
not surgically resectable in that they are advanced at the time
of initial diagnosis. Thus, palliation, often in the form of stent
placement, is the major form of therapy. Prognosis is dismal,
with many patients dying within the first year. Histologically,
these adenocarcinomas are typically well differentiated or mod-
erately differentiated and associated with an extensive desmo-
plastic host response. In most cases obstructive jaundice is not
caused by malignant neoplasms but rather secondary to any
of a number of benign conditions. Causes of benign strictures
include pancreatitis, cholecystitis, gallstones, primary sclerosing
cholangitis, ascending cholangitis, trauma, especially operative,
and papillitis. Cytology plays a major role in distinguishing
benign from malignant strictures.
The two most common cytologic methods for evaluat-
ing biliary ductal epithelium are brushings obtained at endo-
scopic
retrograde
cholangiopancreatography
(ERCP)
and
direct examination of bile and pancreatic juice. The latter may
be obtained through various procedures including T-tube
Fig. 14.31 Benign/reactive bile ductal epithelium. A flat cohesive cluster
sheet of highly uniform epithelial cells shows a well-demarcated smooth
edge. Additionally, the cells exhibit polarity and are bland in appearance.
Although the N/C ratios are focally high, the cells are quite uniform. Note the
absence of individual atypical epithelial cells (Papanicolaou x HP).
401
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