Hiromi Fujita

Hiroshi Hirano

Makoto Emori

Masahiro Iwasaki

Noriaki Kikuchi

Ryoichi Tanaka

Ryuichi Wada

Shintaro Sugita

Tadashi Hasegawa

Taro Sugawara

Terufumi Kubo

Tsuyoshi Saito

Yumika Ito

Diagnostic Pathology

Springer - Publisher Connector

CASE REPORT Open Access
Uterine epithelioid leiomyosarcoma
with c-kit expression and YWHAE gene
rearrangement: a case report of a
diagnostic pitfall of uterine sarcoma
Terufumi Kubo1, Shintaro Sugita1, Ryuichi Wada2, Noriaki Kikuchi1, Masahiro Iwasaki3, Yumika Ito1, Taro Sugawara1,
Hiromi Fujita1, Makoto Emori4, Ryoichi Tanaka3, Hiroshi Hirano1, Tsuyoshi Saito3 and Tadashi Hasegawa1*
Abstract
Background: Uterine sarcoma is a rare tumor that is often difficult to classify based on morphological and
immunohistochemical analysis alone. Limited access to molecular biological analysis in routine practice would
hinder making a definitive diagnosis.
Case Presentation: In this report, we describe a case of a mesenchymal tumor arising from the uterine cervix in a
52-year-old woman. From microscopic morphology of the resected specimen, epithelioid leiomyosarcoma, high-grade
endometrial stromal sarcoma, or uterine gastrointestinal stromal tumor (GIST) were considered as differential diagnoses.
The immunophenotype of the tumor featured smooth muscle differentiation and hormone receptor expression. The
cell membrane and cytoplasm were positive for c-kit, although no mutation was found in the c-kit or PDGFRA gene.
Fluorescence in situ hybridization (FISH) analysis revealed a relatively low frequency of YWHAE rearrangement, whereas
there were few NUTM2A and NUTM2B split signals.
Conclusions: In this case, the tumor was not typical of any three of the differential diagnoses mentioned above.
However, insufficient frequency of YWHAE, NUTM2A, and NUTM2B gene rearrangement and absence of mutation in both
the c-kit and PDGFRA genes suggested that this tumor should be categorized as epithelioid leiomyosarcoma. This is an
instructive case showing a potential diagnostic pitfall of uterine sarcoma. Comprehensive approaches including molecular
biological techniques are required for definitive diagnosis.
Keywords: YWHAE rearrangement, FISH, Uterine leiomyosarcoma, c-kit
Background
Uterine sarcoma is a rare tumor for which diagnosis is
often difficult. According to the 2014 WHO classifica-
tion, uterine sarcoma consists of leiomyosarcoma, low-
and high-grade endometrial stromal sarcoma (ESS), and
undifferentiated sarcoma [1]. Uterine gastrointestinal
stromal tumor (GIST), although not listed in the WHO
classification, is reported in some studies [2]. As newly
identified gene rearrangements or immunophenotypes in
uterine sarcomas may establish novel disease entities,
detailed pathological investigation in each case is
becoming increasingly important for appropriate
evaluation of the tumor.
We encountered an unusual case of mesenchymal
tumor with epithelioid morphology. The tumor arose
from the uterine cervix exhibiting relatively low-
frequency mitosis, smooth muscle differentiation, and
c-kit expression. Furthermore, YWHAE gene rearrange-
ment was detected by fluorescence in situ hybridization
(FISH) in the tumor. These findings were suggestive of
epithelioid leiomyosarcoma, high-grade ESS, or uterine
GIST as differential diagnosis.
* Correspondence: hasetada@sapmed.ac.jp
1Department of Surgical Pathology, School of Medicine, Sapporo Medical
University, South 1, West 16, Chuo-ku, Sapporo, Hokkaido 060-8543, Japan
Full list of author information is available at the end of the article
© The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and
reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver
(http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
Kubo et al. Diagnostic Pathology  (2017) 12:26 
DOI 10.1186/s13000-017-0615-6
Case Presentation
A 52-year-old multiparous Japanese woman was referred
to our hospital with a complaint of a feeling of abdom-
inal fullness. She had uterine leiomyoma that had been
observed for 9 years, and a history of chronic thyroiditis.
Aside from the earlier observed leiomyoma, a previously
unnoticed soft mass at the uterine cervix was palpable
on pelvic examination. T1-weighted magnetic resonance
imaging with fat suppression revealed a swollen uterine
corpus with leiomyoma, and suggested a uterine cervical
lesion with a low signal intensity (Fig. 1). Circulating
levels of CA 125 and CA 19–9 were within the reference
range at 16.3 and 11 U/mL, respectively. Hysterectomy
was performed with a clinical diagnosis of multiple
leiomyomas and an unknown cervical tumor. Postopera-
tively, the patient underwent adjuvant chemotherapy
(gemcitabine plus docetaxel) and did well for the next
3 months, with neither local recurrence nor distant
metastasis on chest and abdominal computed tomog-
raphy imaging.
The enlarged uterus was 8 × 14 × 8.5 cm in size.
Several elastic, hard, whitish masses were found in the
uterine corpus, consistent with leiomyoma. In addition,
an elastic, soft gray-white hemorrhagic mass measuring
8 × 6 × 5 cm was observed at the anterior wall of the
uterine cervix (Fig. 2a).
Histologically, the cervical mass was below the
squamous epithelium and consisted of a nest-like prolif-
eration of less cohesive, epithelioid tumor cells that had
rounded nuclei and eosinophilic cytoplasm. The tumor
cells had no marked nuclear pleomorphism and promin-
ent nucleoli, and a coarse chromatin pattern was found
in the nucleus. Mitotic figures were moderately frequent
(4 per high-power field) but atypical mitoses were not
present (Fig. 2c). The tumor showed a confluent growth
pattern and individual nests of tumor cells were com-
partmentalized by intricate vasculature (Fig. 2b). There
was no apparent involvement of myometrial smooth
muscle cells. Foci of extensive necrosis and hemorrhage
were found in some areas. A low-grade ESS component,
showing uniform cells with round to spindle-shaped nu-
clei, which were whorled around arteriole-type vessels,
was not coexistent in the lesion.
Immunohistochemically, the tumor cells were diffusely
positive for vimentin (clone V9, DAKO, Glostrup,
Denmark), α-smooth muscle actin (αSMA; clone 1A4,
DAKO; Fig. 3a), muscle-specific actin (clone HHF-35,
DAKO), and heavy caldesmon (clone h-CD, DAKO),
with moderate positivity for c-kit (DAKO; Fig. 3b), estro-
gen receptor (ER; clone SP1, Ventana, Tucson, AZ;
Fig. 3c), and progesterone receptor (PgR; clone 1E2,
Ventana). In contrast, the cells were negative for
pan-cytokeratin (clone AE1/AE3, DAKO), desmin (clone
D33, DAKO), CD10 (clone 56C6, Novocastra, Newcastle
upon Tyne, United Kingdom), CD34 (clone QBEnd10,
DAKO), p16 (clone E6H4, Roche, Basel, Switzerland),
DOG1 (clone K9, Leica Biosystems, Wetzlar, Germany)
and cyclin D1 (Biocare, Concord, CA). The Ki-67 (clone
30–9, Roche) labeling index of the neoplastic cells was
19.5%. These histological and immunohistochemical
findings suggested a differential diagnosis of non-epithelial
tumor of the uterus, particularly high-grade ESS,
epithelioid leiomyosarcoma, or uterine GIST.
FISH was performed for further molecular biological
observations. To detect YWHAE rearrangement derived
from chromosomal translocation of t(10;17)(q22;p13)—we
used a custom dual-color, split-signal YWHAE probe set
for the YWHAE locus on chromosome 17p13 (Chromo-
some Science Lab, Inc., Sapporo, Japan). The probe set
consisted of a 333-kilobase (kb) sequence labeled with
SpectrumGreen (telomeric [RP11-143 L7 and RP11-
22G12]) and a 303-kb sequence labeled with SpectrumOr-
ange (centromeric [RP11-100 F18 and RP11-60C18]).
Rearrangements in the NUTM2A and NUTM2B genes at
10q23 and 10q22, respectively, were characterized using a
custom break-apart probe design. The probes were syn-
thesized using oligo-based SureFISH technology (Agilent
Technologies, Santa Clara, CA) and labeled with FITC (5’
probe) and Cy3 (3′ probe) fluorophores. The analysis was
performed with formalin-fixed, paraffin-embedded speci-
mens sectioned into 3-μm-thick slices, as described previ-
ously [3]. The split-signal rate of YWHAE, NUTM2A and
NUTM2B was 18%, (Fig. 3d), 0 and 4%, respectively, when
50 nuclei were counted. In contrast, a JAZF1 split, which
Fig. 1 T1-weighted magnetic resonance imaging with fat
suppression shows a low-signal lesion measuring approximately
4 cm at the uterine cervix (arrowhead)
Kubo et al. Diagnostic Pathology  (2017) 12:26 Page 2 of 5
is a major gene translocation in low-grade ESS, [4] was
not detected.
To investigate KIT and PDGFRA gene mutations,
direct sequence analysis was performed. Exons 9, 11,
and 13 of the KIT gene and exon 18 of the PDGFRA
gene were amplified by polymerase chain reaction using
the primers KITexon9F: GGC TTT TGT TTT CTT
CCC TTT A, KITexon9R: ATG GTA GAC AGA GCC
TAA ACA, KITexon11F: GAT CTA TTT TTC CCT
TTC TCC C, KITexon11R: AGC CCC TGT TTC ATA
CTG AC, KITexon13F: GCT TGA CAT CAG TTT
GCC AG, KITexon13R: GCA GCT TGG ACA CGG
CTT T, PDGFRAexon18F: CAG ATG GCT TGA TCC
TGA GT, and PDGFRAexon18R: GAG GAT GAG CCT
GTC CAG T. The amplified products were purified and
sequenced. The sequences of KIT exons 9, 11, and 13
were wild type. In PDGFRA exon 18, substitution of
nucleotide C to T, known as a single-nucleotide variant
(rs2228230) was detected in one allele. The variant does
not cause amino acid substitution. Thus, it was consid-
ered that there was no oncogenic mutation in KIT and
PDGFRA genes in this tumor.
Discussion
This tumor consisted predominantly of round cells with
a modest amount of eosinophilic to granular cytoplasm,
irregular nuclear contour, and granular to vesicular chro-
matin with variably prominent nucleoli. Neoplastic cells
were arranged in a nest-like structure compartmental-
ized by delicate vasculature. Although the current case
conformed exactly to the morphological definition of
high-grade ESS, the mitotic activity was inconspicuous.
Immunohistochemically, c-kit and cyclin D1 are consid-
ered to be critical markers in diagnosing high-grade ESS
[5, 6]. While the cell membrane and cytoplasm were
positive for c-kit in the current case, there was no
nuclear staining of cyclin D1. The diffuse positive signals
for ER and PgR found in this case are also uncommon
in high-grade ESS. The tumor cells were positive for
some smooth muscle and myogenic markers including
αSMA, muscle-specific actin, and heavy caldesmon,
which have not been previously reported in high-grade
ESS [7]. These immunophenotypes might indicate
epithelioid leiomyosarcoma rather than high-grade ESS.
Fig. 2 Gross and histopathological morphology of the uterine cervical
lesion. a Cut surface of the resected uterus: Whitish masses in the uterine
corpus are typical leiomyomas on gross and microscopic examination. At
the uterine cervix, a gray-white lesion is observed (arrowhead).
b High-power view of the lesion: Tumor cells have an epithelioid
appearance but are less cohesive. Intercellular bridges are absent.
Uniformly rounded nuclei have coarse chromatin and obvious
nucleoli. Original magnification: ×400. c Low-power view of the lesion:
Tumor cells are arranged in a nest-like structure compartmentalized by
a vascular network. Original magnification: ×100
Kubo et al. Diagnostic Pathology  (2017) 12:26 Page 3 of 5
In addition to morphological and immunohistochemical
findings, molecular biological investigations offer a sophis-
ticated approach that provides critical information for
accurately diagnosing some types of bone and soft tissue
tumors. Lee et al. reported that high-grade ESS typically
harbors a YWHAE-NUTM2 fusion gene [8]. The current
case harbored 18% of YWHAE gene rearrangement. Con-
versely, the frequencies of NUTM2A and NUTM2B split
signals were far lower than that of YWHAE. Although a
small number of split signals is considered to be sufficient
evidence of gene rearrangement in the diagnosis for some
types of tumors, a relevant threshold of YWHAE split
signals for diagnosing high-grade ESS under the current
concept is reported to be 20% [9]. Furthermore, YWHAE
gene rearrangement may not be a specific finding for
high-grade ESS. It was reported that translocation of
t(10;17), including the YWHAE gene, was detected in a
uterine sarcoma that was diagnosed as a poorly differenti-
ated uterine tumor with t(10;17) translocation and
neuroectodermal phenotype [10]. The c-kit positivity seen
in the current case might possibly be suggestive of a uter-
ine GIST. However, the results of direct sequencing
revealed that there was no mutation in exons 9, 11, and
13 of the KIT gene or in exon 18 of the PDGFRA gene in
the tumor. Based on all these findings, the tumor was
designated as uterine epithelioid leiomyosarcoma with
c-kit expression and YWHAE gene rearrangement.
Conclusions
In conclusion, the tumor in this case seems quite in-
structive, showing a potential diagnostic pitfall of uterine
sarcoma with epithelioid morphology. The tumor had
some immunohistochemical features of leiomyosarcoma,
high-grade ESS, and uterine GIST. In addition to the
conventional practices for pathological diagnosis,
molecular biological analysis led to a more definitive
diagnosis. Interestingly, this uterine sarcoma exhibited
unusual gene rearrangement for leiomyosarcoma. Accu-
mulation of additional cases may enable an appropriate
evaluation of prognosis, better treatment, and a novel
paradigm for this disease.
Abbreviations
ER: Estrogen receptor; ESS: Endometrial stromal sarcoma; FISH: Fluorescence in situ
hybridization; GIST: Gastrointestinal stromal tumor; PgR: Progesterone receptor
Acknowledgments
None.
Funding
None.
Availability of data and materials
There are no additional supporting data available.
Authors’ contributions
TK and SS carried out histopathological evaluation and drafted the manuscript.
RW performed direct sequencing. NK, YI, TS, HF, and HH assisted with the
pathological analysis. RT, MI, ME, and TS collected the clinical and surgical data.
TH conceived of the study and participated in the design, and the preparation
of the manuscript. All authors read and approved the final manuscript.
Competing interests
There are no conflicts of interests in this study.
Consent for publication
The patient gave general consent for the use of their tissue/data for research
purposes as authorized by the Institutional Review Board of Sapporo Medical
University Hospital (282–65). Written informed consent for publication of
Fig. 3 a to c Immunohistochemical analysis of the tumor. Tumor cells are positive for a α-smooth muscle actin, b c-kit, and c estrogen receptor.
Original magnification: ×100. d Fluorescent in situ hybridization analysis: Arrow indicates non-split signal. Arrowheads indicate split signals. A split
signal for the YWHAE gene is detected in 18% of tumor cells
Kubo et al. Diagnostic Pathology  (2017) 12:26 Page 4 of 5
clinical details and clinical images was obtained from the patient. A copy of
the consent form is available for review by the Editor of this journal.
Ethics approval and consent to participate
The ethical approval and documentation for a case report was waived with
approval of the Institutional Review Board of Sapporo Medical University Hospital.
Author details
1Department of Surgical Pathology, School of Medicine, Sapporo Medical
University, South 1, West 16, Chuo-ku, Sapporo, Hokkaido 060-8543, Japan.
2Department of Integrated Diagnostic Pathology, Nippon Medical School,
Tokyo, Japan. 3Department of Obstetrics and Gynecology, School of
Medicine, Sapporo Medical University, Sapporo, Japan. 4Department of
Orthopaedic Surgery, School of Medicine, Sapporo Medical University, South
1, West 16, Chuo-ku, Sapporo, Hokkaido 060-8543, Japan.
Received: 4 January 2017 Accepted: 27 February 2017
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Uterine epithelioid leiomyosarcoma with c-kit expression and YWHAE gene rearrangement: a case report of a diagnostic pitfall of uterine sarcoma

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Uterine epithelioid leiomyosarcoma with c-kit expression and YWHAE gene rearrangement: a case report of a diagnostic pitfall of uterine sarcoma

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