PART TWO
Diagnostic Cytology
receptor analysis, flo w cytom etry, and m olec ular diagnostic
studies. The advantages o f th e FN A procedure also include accu-
rate diagnosis, excellent p a tie nt acceptance, and m in im a l o r no
m o rb id ity .18-20
Limitations of FNA of the Breast
There were in itia l reservations expressed ab out accepting the
procedure because o f the need fo r an experienced cytop atholo-
gist to inte rp ret the aspirated m ate ria l.21 FN A is dependent on
the experience and skills o f those p e rform in g the procedure, as
w e ll as good tra in in g in the cytology.22,23 Technical problem s
such as lim ite d cellularity, excessive a ir d rying a n d /o r artifactual
m echanical disaggregation can p o te n tia lly lim it the interp reta-
tio n , as w e ll as contrib ute to a false-negative o r a false-positive
diagnosis o f m alignancy, respectively (Fig. 25.1).24 However, in
o u r experience as w e ll as th a t o f others, the m a jo r current lim ita -
tio n o f FN A b iopsy is th e separation o f atypical ductal hyperplasia
(A D H ) fro m ductal carcinom a in situ (D C IS ) and d iffe re n tia ting
D C IS fro m invasive carcinom a, w h ic h affect the patient's treat-
m e n t.25-29 O th e r lim itin g factors includ e occasional in a b ility to
m ake a d e fin itive m a lig n a n t diagnosis o f low -grade carcinom a,
B
Fig. 25.1 (A)
ups of atypical spindle-shaped cells showing
considerable air-drying artifact in aspirate from a nodule arising in a
mastectomy scar. Clinically, recurrent breast carcinoma was suspected
(Diff-Quik x MP). (B) Surgical confirmation demonstrating leiomyoma
rather than recurrent breast carcinoma in a mastectomy scar. The case
demonstrates that definitive diagnosis should not be rendered on
ill-prepared material with limited cellularity (H&E x HP).
such as tu b u la r carcinom a o r invasive lo b u la r carcinom a, p ap il-
la ry and fib ro e p ith e lia l lesions, and d ifferentiate p rim a ry fro m
m etastatic carcinom a.25,30-34 A n o th e r m a jo r concern in breast
FN A b iop sy is the p o ten tial false-positive diagnoses in the
asp iration o f a n um b er o f benign reactive, inflam m ato ry, and
m etaplastic breast lesions, p ro m p tin g inap p rop riate treatm ent
having clinical and m edicolegal im p lic a tio n s.26,35
Finally, one issue th a t has n o t been com p letely addressed in
the lite rature is the im p o rta n t q uestion o f w h a t constitutes an
adequate FN A breast aspirate.36-40 It is generally accepted th a t
samples th a t lack e p ith elial cells are considered inadequate,
w ith certain exceptions such as aspirates o f clinical lip o m a s o r
lym p h nodes. T he M D A nderson Cancer Center G roup proposes
th a t fo u r to six w ell-visualized cell groups consisting o f at least
six cells in each cluster and m ore th a n ten cells per fla t sheet
constitute an adequate specim en.38,40,41 O n occasion, the diagno-
sis o f breast carcinom a can be m ade o n a scantly cellular speci-
m en, w h ile o th e r cases having ab und ant c e llu la rity m ay n o t
lend them selves to a d e fin itive diagnosis.22 O n ly experience and
good jud g m ent can a llo w th is decision to be m ade reliab ly.39,41
Role of FNA in the Era of CNB
In the past, there had been considerable interest in p e rform -
ing FN A b iopsy o f nonp alp ab le m am m ographically-detected
breast lesions using specialized lo c a liza tio n guidance systems,
since FN A can increase the specificity o f th e m am m og rap hic
study.42-50 However, in the past 10 years, the p o p u la rity o f the
FN A o f nonp alp ab le breast lesions has been challenged b y the
in tro d u c tio n o f CNB. A lth o u g h som e studies showed th a t b o th
techniques have com parable sensitivities fo r diagnosing breast
lesions,51-57 CNB has n o w becom e the standard procedure in
m an y m edical centers in the U n ite d States fo r the evaluation o f
nonp alp ab le breast lesions.58-63 T he fin a l death kn e ll fo r FN A o f
m am m og rap hic lesions m ay have been delivered w ith the pub-
lic a tio n o f a m u ltiin s titu tio n a l study rep orting sup erior results
w ith CNB over FN A biopsy, in w h ic h there was a sig nificant hig h
false-negative rate w ith FN A at the p articip ating centers o f the
study.64
For palpable breast lesions FN A is s till used, b u t it also
appears to be ra p id ly d eclining in favor o f C N B.20,58,63 Cobb and
Raza have suggested a variety o f reasons fo r the possible demise
o f breast FNA, inc lu d in g (1 ) FN A cytology's in a b ility to separate
in situ fro m invasive carcinom a, (2 ) CNB is needed to provide
tissue fo r a nc illa ry studies, (3) clinical trials req u iring a h is to -
logic diagnosis, (4) a diagnosis o f breast cancer s till needs to
be confirm ed b y CNB o r frozen section, and (5) cytopathology
expertise in FN A is n o t always available at m an y hosp itals.65
It n o w appears th a t breast FN A b iop sy is being p erform ed fo r
com p leting the trip le test to con firm a negative diagnosis rather
th an establishing a diagnosis o f m alignancy.63,66 Lau et al. have
reported th a t in a setting o f a negative trip le test, the negative
predictive value o f breast FN A was 100%, reassuring the p a tie nt
and c linician th a t clinical fo llo w -u p rather th an surgical in te r-
v e n tio n was the appropriate care.67 X ie et al. also reported th a t
after th e im p le m e n ta tio n o f CNB, the types o f cases (b u t n o t the
to ta l n um b er) has changed, w ith a sig nificant increase in the
negative/unsatisfactory cases at th e ir in s titu tio n .68 O u r experi-
ence is s im ila r to th a t o f X ie et al.,68 w ith FN A being increasingly
used to com plete the trip le test in c lin ic a lly and rad iog rap hi-
cally appearing benign breast cases. M oreover, FN A can also
q u ic kly and accurately establish a specific diagnosis o f a variety
714
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