Introduction: In fine-needle aspiration of the breast (FNAB), the “atypical” category encompasses both benign and malignant lesions, particularly papillary proliferative lesions, as per the latest WHO classification. We aimed to reduce atypical cases and improve diagnostic accuracy by investigating the utility of cell block (CB) analysis. Methods: FNAB CB samples (2018–2022) were reviewed using smear only or CBs. CB-based diagnosis was performed with 2D morphological analysis and immunocytochemistry using ER, CK5/6, p63, SMA, and CD56. Samples were reclassified as “benign,” “atypical,” “suspicious of malignancy,” “malignant,” or “insufficient/inadequate.” Atypical cases were reexamined. Diagnoses were validated histologically. Results: On examining the FNAB samples (n = 149; 32 atypical), 2D CB sectioning achieved a clearer definition of myoepithelial cells and fibrovascular cores than Papanicolaou staining. Immunocytochemistry was evaluated for 36 cases: estrogen receptor (ER) and CK5/6+ tumors were reclassified as benign; ER+ and CK5/6 tumors as malignant; p63 tumors as invasive; papillary malignant tumors with a smooth muscle actin (SMA)+ fibrovascular core and p63 myoepithelial cells as encapsulated papillary carcinoma; and CD56+ carcinomas as neuroendocrine carcinoma. Diagnostic rates were as follows: benign (44% FNAB, 51% CB), atypical (21% FNAB, 3% CB), suspicious of malignancy and malignant (28% FNAB, 40% CB), and insufficient/inadequate (7% FNAB, 6% CB). CB achieved >85% sensitivity, specificity, and positive and negative predictive values. Conclusion: CBs represent 3D FNA cell morphology using 2D sections, enabling adaption of pathology criteria to the cytological material. Immunocytochemical staining of CBs can predict low nuclear grade papillary tumors and reduce atypical case frequency, improving diagnostic accuracy.

1.
WHO Classification of Tumours Editorial Board
WHO classification of tumors: breast tumors
5th ed
Lyon
IARC
2019
.
2.
Obiajulu
FJN
,
Daramola
AO
,
Anunobi
CC
,
Ikeri
NZ
,
Abdulkareem
FB
,
Banjo
AA
.
The diagnostic utility of cell block in fine needle aspiration cytology of palpable breast lesions in a Nigerian tertiary health institution
.
Diagn Cytopathol
.
2020 Dec
48
12
1300
6
.
3.
Field
AS
,
Raymond
WA
,
Rickard
M
,
Arnold
L
,
Brachtel
EF
,
Chaiwun
B
.
The international Academy of cytology Yokohama System for reporting breast fine-needle aspiration biopsy cytopathology
.
Acta Cytol
.
2019
;
63
(
4
):
257
73
.
4.
Boerner
S
,
Fornage
BD
,
Singletary
E
,
Sneige
N
.
Ultrasound-guided fine-needle aspiration (FNA) of nonpalpable breast lesions: a review of 1,885 FNA cases using the National Cancer Institute-supported recommendations on the uniform approach to breast FNA
.
Cancer
.
1999 Feb
87
1
19
24
.
5.
Kanhoush
R
,
Jorda
M
,
Gomez-Fernandez
C
,
Wang
H
,
Mirzabeigi
M
,
Ghorab
Z
.
Atypical’ and “suspicious” diagnoses in breast aspiration cytology: is there a need for two categories
.
Cancer Cytopathol
.
2004 Jun
102
3
164
7
.
6.
Symmans
WF
,
Weg
N
,
Gross
J
,
Cangiarella
JF
,
Tata
M
,
Mazzo
JA
.
A prospective comparison of stereotaxic fine-needle aspiration versus stereotaxic core needle biopsy for the diagnosis of mammographic abnormalities
.
Cancer
.
1999 Mar
85
5
1119
32
.
7.
Westenend
PJ
,
Sever
AR
,
Beekman-de Volder
HJ
,
Liem
SJ
.
A comparison of aspiration cytology and core needle biopsy in the evaluation of breast lesions
.
Cancer Cytopathol
.
2001 Apr
93
2
146
50
.
8.
Al-Maghraby
H
,
Ghorab
Z
,
Khalbuss
W
,
Wong
J
,
Silverman
JF
,
Saad
RS
.
The diagnostic utility of CK5/6 and p63 in fine-needle aspiration of the breast lesions diagnosed as proliferative fibrocystic lesion
.
Diagn Cytopathol
.
2012 Feb
40
2
141
7
.
9.
Istvanic
S
,
Fischer
AH
,
Banner
BF
,
Eaton
DM
,
Larkin
AC
,
Khan
A
.
Cell blocks of breast FNAs frequently allow diagnosis of invasion or histological classification of proliferative changes
.
Diagn Cytopathol
.
2007 May
35
5
263
9
.
10.
Chan
RCK
,
Li
JJX
,
Yeung
W
,
Chan
AWH
.
Virtual multiplex immunohistochemistry: application on cell block of effusion and aspiration cytology
.
Diagn Cytopathol
.
2020 May
48
5
417
23
.
11.
Harton
AM
,
Wang
HH
,
Schnitt
SJ
,
Jacobs
TW
.
p63 immunocytochemistry improves accuracy of diagnosis with fine-needle aspiration of the breast
.
Am J Clin Pathol
.
2007 Jul
128
1
80
5
.
12.
O’Neil
S
,
Castelli
M
,
Gattuso
P
,
Kluskens
L
,
Madsen
K
,
Aranha
G
.
Fine-needle aspiration of 697 palpable breast lesions with histopathologic correlation
.
Surgery
.
1997 Oct
122
4
824
8
.
13.
Michael
CW
,
Buschmann
B
.
Can true papillary neoplasms of breast and their mimickers be accurately classified by cytology
.
Cancer
.
2002 Apr
96
2
92
100
.
14.
Mansoor
I
,
Jamal
AA
.
Role of fine needle aspiration in diagnosing breast lesions
.
Saudi Med J
.
2002 Aug
23
8
915
20
.
15.
Ariga
R
,
Bloom
K
,
Reddy
VB
,
Kluskens
L
,
Francescatti
D
,
Dowlat
K
.
Fine-needle aspiration of clinically suspicious palpable breast masses with histopathologic correlation
.
Am J Surg
.
2002 Nov
184
5
410
3
.
16.
Azzarelli
A
,
Guzzon
A
,
Pilotti
S
,
Quagliuolo
V
,
Bono
A
,
Di Pietro
S
.
Accuracy of breast cancer diagnosis by physical, radiologic and cytologic combined examinations
.
Tumori
.
1983 Apr
69
2
137
41
.
17.
Medina-Franco
H
,
Abarca-Pérez
L
,
Cortés-González
R
,
Soto-Germes
S
,
Ulloa
JA
,
Uribe
N
.
Biopsia por aspiración con aguja fina en lesiones mamarias: experiencia institucional [Fine needle aspiration biopsy of breast lesions: institutional experience
.
Rev Invest Clin
.
2005 May
57
3
394
8
.
18.
Mulford
DK
,
Dawson
AE
.
Atypia in fine needle aspiration cytology of nonpalpable and palpable mammographically detected breast lesions
.
Acta Cytol
.
1994 Jan–Feb
38
1
9
17
.
19.
Willis
SL
,
Ramzy
I
.
Analysis of false results in a series of 835 fine needle aspirates of breast lesions
.
Acta Cytol
.
1995 Sep–Oct
39
5
858
64
.
20.
Howell
LP
.
Equivocal diagnoses in breast aspiration biopsy cytology: sources of uncertainty and the role of “atypical/indeterminate” terminology
.
Diagn Cytopathol
.
1999 Sep
21
3
217
22
.
21.
al-Kaisi
N
.
The spectrum of the “gray zone” in breast cytology. A review of 186 cases of atypical and suspicious cytology
.
Acta Cytol
.
1994 Nov–Dec
38
6
898
908
.
You do not currently have access to this content.