Correspondence
correspondence
CDX2 Expression in Some Variants of Papillary Thyroid Carcinoma
DOI: 10.1309/AJCP1BGCA6MFCNKH
To the Editor
The publication of the article of Enriquez et al1
coincided with the final steps of our study on the
expression of CDX2 in normal and neoplastic follicularderived cells of the human thyroid gland. Enriquez et
al1 evaluated CDX2 expression in 11 cases of columnar
cell variant (CCV) of papillary thyroid carcinoma (PTC)
and in thyroid tissue microarrays (TMAs) composed of
normal tissue, 38 cases of benign lesions (Hashimoto
disease, Graves disease, lymphocytic thyroiditis,
multinodular goiter, and papillary hyperplasia), and 33
samples of neoplastic conditions (8 follicular carcinomas,
9 conventional PTC, 2 tall cell variants of PTC, 2 poorly
differentiated carcinomas, 6 anaplastic carcinomas, 4
medullary carcinomas, 4 Hürthle cell adenomas, and 2
follicular adenomas). Enriquez et al1 identified CDX2
expression in 6 (55%) of the 11 cases of CCV of PTC, but
not in any other benign or malignant thyroid lesions. They
only found focal or diffuse CDX2 immunoreactivity in
tumors with pure columnar cell morphologic features (6/9
cases) but not in 2 cases with only focal columnar cell/
mixed features. They concluded that CDX2 is selectively
expressed in CCV of PTC and can be used to distinguish it
from other variants of PTC with overlapping morphologic
features.
We used a TMA composed of 10% formalin-fixed,
paraffin-embedded thyroid tissue samples: 50 follicular
adenomas, 75 PTCs (35 classic subtype, 27 follicular
variant, 4 solid variant, 3 tall cell variant, 2 diffuse
sclerosing variant, 4 cribriform morular variant [CMV;
2 sporadic and 2 associated with familial adenomatous
polyposis]), 48 follicular carcinomas (34 minimally
invasive, 14 widely invasive), 15 poorly differentiated
carcinomas (6 insular variant, 9 noninsular), 13
undifferentiated (anaplastic) carcinomas, and 15 normal
thyroid tissue. The TMA was built using a tissue arrayer
device (Beecher Instruments, Sun Prairie, WI), including
duplicate 1.6-mm cores of each type of tissue per case. All
216 samples and additional controls were collected from
files of the Pathology Department of Clinical University
Hospital of Santiago de Compostela, Spain. Clinical
© American Society for Clinical Pathology
data were collected from the pathology reports and
clinical files. The local ethics and scientific committees
approved this study. H&E slides were simultaneously
reviewed by 2 pathologists (J.C.-T. and L.A.-L.) and the
tumors classified using the World Health Organization
criteria2 with the Turin proposal for poorly differentiated
carcinomas3; cases with doubtful PTC features were
excluded. The immunohistochemical study was performed
on 4-μm-thick paraffin sections of the TMA blocks
using a peroxidase-conjugated dextran-labeled polymer
(EnVision FLEX, Dako, Glostrup, Denmark) to avoid
misinterpreting endogenous biotin or biotin-like activity
in cell cytoplasm or in nuclei as positive staining, with an
automated link platform (Autostainer Link 48, Dako). The
primary antibodies were used as follows: CDX2 (clone
DAK-CDX2, ready-to-use, 30 minutes, high pH, Dako),
thyroid transcription factor-1 (TTF-1) (clone 8G7G3/1,
ready-to-use, 30 minutes, low pH, Dako), thyroglobulin
(polyclonal, ready-to-use, 20 minutes, low pH, Dako), and
calcitonin (polyclonal, ready-to-use, 20 minutes, high pH,
Dako). In the interpretation of positive immunoreactivity
against anti-CDX2, only unequivocal nuclear staining was
considered positive.
The main clinical data of patients and the
immunostaining results are listed in ❚Table 1❚. All cases
were negative for calcitonin, and all samples, except for
the undifferentiated carcinomas, were positive for TTF-1
❚Image 1E❚ and ❚Image 1F❚. Thyroglobulin expression
was noted in all adenomas, well-differentiated carcinomas
(excluding the 4 cases of CMV of PTC), and poorly
differentiated carcinomas, but no reactivity was found
in undifferentiated carcinomas. Interestingly, strong and
diffuse nuclear CDX2 was only detected in all tumor
cells of 1 case of classic PTC ❚Image 1A❚ and ❚Image 1C❚
and in the morular foci of the 4 cases of CMV of PTC
❚Image 1B❚ and ❚Image 1D❚. All H&E slides from the only
CDX2-positive classic PTC were re-revised, but columnar
cell features were not found, and CDX2 positivity was
confirmed in additional paraffin blocks of this case. This
PTC occurred in a 40-year-old woman (T2N0M0) treated
Am J Clin Pathol 2012;138:907-910 907
Correspondence
❚Table 1❚
CDX2, TTF-1, Thyroglobulin, and Calcitonin Expression in Normal and Neoplastic Follicular Cells of the Thyroid
Type of Sample
No.
Mean (Range)
Age, y
Female Sex,
No. (%)
CDX2
Normal thyroid
Follicular adenoma
Papillary carcinoma
Follicular carcinoma
Poorly differentiated carcinoma
Undifferentiated carcinoma
59.4 (25-81)
46.02 (14-82)
47.64 (11-83)
50.4 (21-78)
65.7 (37-83)
66.2 (41-82)
6 (40)
42 (84)
56 (74.6)
34 (70.8)
11 (73.3)
8 (61.5)
0
15
15
0
0
50
50
0
5*7571†0
0
48
48
0
0
15
15
0
0
0
0
0
15
50
75
48
15
13
TTF-1
TG
CT
TTF-1, thyroid transcription factor-1; TG, thyroglobulin; CT, calcitonin.
* Includes 1 case of classic papillary carcinoma and 4 cases of cribriform morular variant of papillary carcinoma.
† The 4 negative cases were the cribriform morular variant of papillary carcinoma.
with total thyroidectomy, radioactive iodine (100 mCi),
and thyroid-stimulating hormone suppression, and the
patient is well with no evidence of disease 111 months
after surgery.
We agree with Enriquez et al1 that CDX2 expression is
detected in some PTCs; however, because we found strong
CDX2 expression in 1 case of classic PTC, we cannot
confirm that CDX2 is exclusively expressed in the CCV of
PTC. The diagnosis of CCV of PTC should be made on the
basis of morphologic features. Because CDX2 expression
is limited to the morular foci in the CMV of PTC and
because CCV of PTC shows significant morphologic
overlap with the CMV of PTC (pseudostratified columnar
cells, coexistence of solid areas, and elongated empty
follicles resembling tubular glands),4,5 we believe that
CDX2 may play a role in cell differentiation in these 2
types of PTC. Our results show, on the other hand, that
CDX2 expression has limited usefulness as a marker for
distinguishing CCV of PTC from other PTC variants.
The aberrant nuclear CDX2 expression in morular
structures was previously reported in different organs.6-8
CDX2, an intestine-specific homeobox gene transcription
factor, is not only expressed in normal intestinal mucosa
but also in colonic adenocarcinoma and nongastrointestinal
tumors.9,10 Morular structures sharing a selective
expression of CDX26,7 and CD1011 have a very low
proliferative index12 and characterize the so-called “family
tumors containing morules with cells displaying biotin-rich
optically clear nuclei,”11 but the biological meaning of
these morphologic structures remains unknown.
The apparently incongruent CDX2 expression in some
PTCs fits very well with the intestinal-like (“noncommitted
differentiation”) phenotype that our group proposed
for PTCs many years ago.13 Along with the papillary
(“villous”) architecture, mucin production, high-molecularweight keratin expression, and infiltrative growth
pattern with lymph node metastasis, CDX2 expression
additionally supports our hypothesis of an intestinal line
of differentiation for PTCs in contrast to an endocrine-like
line for follicular carcinomas and a neuroendocrine-like
line for medullary carcinomas.13
This study was supported by grant PS09/02050-FEDER
from Instituto de Salud Carlos III, Ministry of Economy and
Competitiveness, Madrid, Spain.
José Cameselle-Teijeiro, MD, PhD
Lara Alberte-Lista, MD
Diego Peteiro-González, MD
Ihab Abdulkader-Nallib, MD, PhD
Rosa Reyes-Santías, MD, PhD
Department of Pathology
Clinical University Hospital
Health Research Institute of Santiago de Compostela (IDIS)
University of Santiago de Compostela
Santiago de Compostela, Spain
Paula Soares, PhD
Manuel Sobrinho-Simões, MD, PhD
Pathology Department
Institute of Molecular Pathology and Immunology
of the University of Porto (IPATIMUP)
Hospital de São João
Porto, Portugal
References
1. Enriquez ML, Baloch ZW, Montone KT, et al. CDX2 expression in columnar cell variant of papillary thyroid carcinoma.
Am J Clin Pathol. 2012;137:722-726.
2. DeLellis RA, Lloyd RV, Heitz PU, et al, eds. World Health
Organization Classification of Tumours: Pathology and Genetics
of Tumours of Endocrine Organs. Lyon, France: IARC Press;
2004.
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Am J Clin Pathol 2012;138:907-910
3. Volante M, Collini P, Nikiforov YE, et al. Poorly differentiated thyroid carcinoma: the Turin proposal for the use of
uniform diagnostic criteria and an algorithmic diagnostic
approach. Am J Surg Pathol. 2007;31:1256-1264.
4. Cameselle-Teijeiro J, Chan JK. Cribriform-morular variant of
papillary carcinoma: a distinctive variant representing the sporadic counterpart of familial adenomatous polyposis-associated
thyroid carcinoma? Mod Pathol. 1999;12:400-411.
© American Society for Clinical Pathology
Correspondence
A
B
C
D
E
F
❚Image 1❚ Classic papillary thyroid carcinoma (A) showing diffuse nuclear expression of CDX2 (C) and thyroid transcription
factor-1 (E). Cribriform morular variant of papillary thyroid carcinoma (B) showing nuclear expression of CDX2 in morular foci
(D) and diffuse nuclear positivity for thyroid transcription factor-1 (F) (A-F, ×400).
© American Society for Clinical Pathology
Am J Clin Pathol 2012;138:907-910 909
Correspondence
5. Cameselle-Teijeiro J, Menasce LP, Yap BK, et al. Cribriformmorular variant of papillary thyroid carcinoma: molecular
characterization of a case with neuroendocrine differentiation
and aggressive behavior. Am J Clin Pathol. 2009;131:134-142.
6. Houghton O, Connolly LE, McCluggage WG. Morules in
endometrioid proliferations of the uterus and ovary consistently express the intestinal transcription factor CDX2.
Histopathology. 2008;53:156-165.
7. Wani Y, Notohara K, Fujisawa M. Aberrant expression of an
“intestinal marker” Cdx2 in pyloric gland adenoma of the gallbladder. Virchows Arch. 2008;453:521-527.
8. Wani Y, Notohara K, Nakatani Y, et al. Aberrant nuclear
Cdx2 expression in morule-forming tumours in different
organs, accompanied by cytoplasmic reactivity. Histopathology.
2009;55:465-468.
9. Saad RS, Ghorab Z, Khalifa MA, et al. CDX2 as a marker for
intestinal differentiation: its utility and limitations. World J
Gastrointest Surg. 2011;3:159-166.
The Authors’ Reply
We thank Dr Cameselle-Teijeiro and colleagues for their
interest in our article on CDX2 expression in the columnar
cell variant (CCV) of papillary thyroid carcinoma (PTC).
We are happy to know that they share an interest in CDX2
expression in thyroid cancer and read their finding of CDX2
expression in a few classic PTCs with great interest.
To date we have seen CDX2 expression only in tumors
with CCV histology, but similar to their findings, we have
also observed CDX2 expression in tumors with cribriform
morular variant (CMV) histology (unpublished data). Similar
to the experience of Dr Cameselle-Teijeiro et al, we have
also observed that the cytology of CCV and CMV is similar
to that seen in colonic adenomas; this makes the CDX2
expression even more interesting. However, we have not
observed other gastrointestinal immunophenotypes, most
notably cytokeratin 20 expression, in any thyroid tumors with
CDX2 expression.
We applaud the effort by Cameselle-Teijeiro et al to
evaluate CDX2 in a larger series of PTCs; it enhances our
understanding of CDX2 expression in thyroid carcinoma
of noncolumnar morphology. Their finding of 1 (1.4%)
of 71 PTCs (excluding the 4 CMV) does not statistically
contraindicate findings of our prior study, which found no
CDX2 expression in 11 PTCs. Rather, it confirms our prior
finding that CDX2 is not normally expressed in thyroid
cancers of noncolumnar type. It would be interesting to know
whether the whole section of the CDX2-positive classic PTC
has been evaluated to assume the finding of “strong and
910
Am J Clin Pathol 2012;138:907-910
10. Khor TS, Alfaro EE, Ooi EM, et al. Divergent expression of
MUC5AC, MUC6, MUC2, CD10, and CDX-2 in dysplasia
and intramucosal adenocarcinomas with intestinal and foveolar morphology: is this evidence of distinct gastric and intestinal pathways to carcinogenesis in Barrett esophagus? Am J
Surg Pathol. 2012;36:331-342.
11. Cameselle-Teijeiro J, Alberte-Lista L, Chiarelli S, et al. CD10
is a characteristic marker of tumours forming morules with biotin-rich, optically clear nuclei that occur in different organs.
Histopathology. 2008;52:389-392.
12. Lin MC, Lomo L, Baak JP, et al. Squamous morules are functionally inert elements of premalignant endometrial neoplasia.
Mod Pathol. 2009;22:167-174.
13. Cameselle-Teijeiro J, Febles-Pérez C, Sobrinho-Simões M.
Papillary and mucoepidermoid carcinoma of the thyroid with
anaplastic transformation: a case report with histologic and
immunohistochemical findings that support a provocative histogenetic hypothesis. Pathol Res Pract. 1995;191:1214-1221.
diffuse (all tumor cells)” CDX2 reactivity in this case, as
shown on the thyroid tissue microarray sample.
In principle, all histologic diagnosis should be
made based on morphologic evaluation rather than
immunohistochemical staining only. We agree that criteria
to differentiate CCV from classic PTC are purely based on
morphologic features rather than immunohistochemical
findings. Even in our prior study, some of the CCVs were
CDX2 negative but were still classified as CCV. The same
principle should apply to a morphologic classic PTC with
CDX2 reactivity. However, the strikingly overwhelming
difference in CDX2 expression between CCV (at least 55%)
and classic PTCs (0%-1.4%) does indicate to pathologists that
CDX2 has a useful ancillary role when columnar morphology
is questionable. We believe the more important intent of our
study is to report the high incidence of CDX2 expression in
CCV thyroid cancer and caution pathologists that CDX2positive tumor without papillary or follicular features could
be a thyroid primary, and that a CDX2-positive tumor with
columnar morphology in the thyroid does not always have a
gastrointestinal primary origin.
Mirian Enriquez, MD
Zubair Baloch, MD, PhD
Kathleen Montone, MD
Paul Zhang, MD
Virginia A. LiVolsi, MD
University of Pennsylvania Medical Center
Philadelphia, PA
© American Society for Clinical Pathology