Epstein-Barr Virus-Positive Leiomyosarcoma in Immunocompetent Patients
Hassan AL-TARAWNEH1, Alpaslan ALP2, Gokhan GEDIKOGLU3, Kemal KOSEMEHMETOGLU3
1Mutah University, Faculty of Medicine, AL-KARAK, JORDAN
2Department of Microbiology, Hacettepe University, Faculty of Medicine, ANKARA, TURKEY
3Department of Pathology, Hacettepe University, Faculty of Medicine, ANKARA, TURKEY
Keywords: EBER, Smooth muscle tumor, EBV, Leiomyosarcoma
Epstein-Barr Virus–Associated Smooth Muscle Tumor (EBV-SMT) is a rare tumor with a higher rate of occurrence in unusual
locations in the setting of immunodeficiency. In this study, we evaluated a cohort of ordinary leiomyosarcomas (LMS) for the presence of EBV
and described the clinicopathological features deviating from routinely diagnosed cases of EBV-SMT.
Material and Method: The sections of tissue microarrays including 93 classical LMS occurring in various locations were hybridized with EBER
and stained for LMP1 antibody using the Leica Bond Autostainer. EBV real-time PCR assay was performed in 2 EBER-positive cases.
Results: Among the 93 LMS cases, 2 non-uterine cases (2.2%) were positive for EBER and negative for LMP1, and were referred to as “EBV-positive
LMS”. Both were females in their 6th decade without immunosuppression. EBV real-time PCR assay revealed the presence of EBV in one of
the cases. Tumors were located in the pancreas and chest wall. Morphologically, tumors were rather myxoid, multinodular, and composed
of long fascicles of spindle cells with intermediate- to high-grade features. High mitotic activity and focal necrosis were present, whereas no
accompanying lymphocytes were detected. One of the patients developed metastatic disease after 3 years.
Conclusion: EBV-positive LMS occurring in immunocompetent patients has features distinct from classical EBV-SMT seen in immunosuppressed
Epstein-Barr Virus–Associated Smooth Muscle Tumor
(EBV-SMT) is considered a rare tumor that has a high rate of
occurrence in unusual locations in the setting of immunodeficiencies,
such as congenital immunodeficiency syndromes,
particularly in children, and in relation to the acquired immunodeficiency
syndrome (AIDS) or organ transplantation in
young adults. Characteristically, it consists of short fascicles of
immature neoplastic cells showing smooth muscle differentiation,
mild nuclear atypia, low mitotic activity, accompanying
lymphocytes, and EBV positivity 1-6
. Although EBV-SMT
is described in detail in immunocompromised individuals,
the presence of EBV in classical LMS of immunocompetent
patients could not be shown before in a relatively small series
. In this study, we performed in-situ hybridization (ISH)
for Epstein-Barr Virus Encoded RNA (EBER) in a cohort of 93
classical leiomyosarcoma (LMS) cases to detect the incidence
of EBV in ordinary LMS and describe the morphological features of EBV-positive LMS with special emphasis on deviating
features from EBV-SMT.
Four blocks of 3-4 mm diameter tissue microarrays composed
of 93 classical LMSs of different locations (55 uterine and 38
non-uterine) were investigated for the presence of EBV. ISH
for EBER (Leica Bond Ready to Use ISH) and LMP1 (Thermo,
CS1+CS2+CS3+CS4 cocktail, ER2 10 min, 1:100) immunohistochemistry
were performed on the tissue microarray
slides using the Leica Autostainer Bond Max2. Diffuse nuclear
staining for EBER and cytoplasmic staining for LMP1 were
regarded as positive. For clinicopathological comparison, 7
consequent cases diagnosed as EBV-SMT between 2000 and
2018 were retrieved from the pathology archives, and the relevant
clinicopathological findings were recorded. A consult
case of a 77-year-old female with multiple masses in the thigh,
pancreas, and lung was excluded due to the limited core biopsy
taken from the lung, lack of clinicopathological correlation, diffuse CD10, and focal desmin and SMA expression, despite
morphological features consistent with EBV-SMT or LMS
and patchy EBER positivity.
The deparaffinization process was applied to the specimens of
the two EBER-positive LMS cases that contained five sections
of 10 mm. Nucleic acid extraction from the specimen was performed
by using the m2000 sp automated extraction instrument
(Abbott Molecular Inc., USA). After the DNA extraction
step, the detection of EBV was performed by using the Abbott
Real-Time EBV PCR kit (Abbott Molecular Inc., USA) in the
m2000 rt real-time PCR instrument. The amplification target
was a highly conserved region of the BLLF1 gene that encodes
the gp350/220 envelope glycoprotein. Internal control was
also used to check the overall internal process, including DNA
extraction and possible PCR inhibition. The manufacturer’s
lower limit of detection was reported as 115 IU/mL.
Among 93 classical LMS, only 2 cases (2% of all LMS, 5% of
all non-uterine LMS) were positive for EBER, both of which
were non-uterine cases, with one located within the pancreas,
and the other on the chest wall. These patients had no known
history of congenital or acquired immunosuppression, autoimmune
disease, or steroid use. HIV tests were negative in
both patients. White blood cell counts were 6100/mL (28%
lymphocytes) and 9600/mL (%32 lymphocytes), respectively.
Clinicopathological characteristics are summarized in Table
. LMP1 was negative in both cases. The EBV real-time PCR
assay was positive in one of the cases (case 2).
The first case was a 56-year-old female with a 19x8x8 cm
mass at the body and tail of the pancreas. She also had a 5 cm,
exophytic right renal mass, diagnosed as conventional renal
cell carcinoma following radical nephrectomy performed 2
months after pancreatectomy and splenectomy. On macroscopy,
a cream-colored, well-circumscribed, solid, multinodular
tumor with a stellate scar at the center was located in the
body of the pancreas and was also closely associated with the
surrounding vascular structures (Figure 1A). Morphologically, the multinodular tumor was composed of long fascicles of
spindle cells with myxoid background and intermediate-grade
features (Figure 1). Focal areas of higher nuclear grade, epithelioid
cells, necrosis, and vascular invasion were present. Mitosis
was 1-2/10 HPF. Neoplastic cells were positive for SMA,
desmin, CD34, and EMA while S100 and c-kit were negative.
She received adjuvant chemotherapy and underwent several
metastatectomies of the lung and liver after 3 years and 6 years,
respectively. Metastases were consistent with leiomyosarcoma
(Figure 2). Two years later, a 2 cm left kidney mass was taken
out by partial nephrectomy and diagnosed as type 1 papillary
renal cell carcinoma. She was lost to follow up with enlarging
pulmonary metastatic nodules after 7 years.
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|Figure 1: EBV-positive LMS Case #1: A) Solid, fleshy, cream-colored tumor with a central stellate scar. Also, note the close relation
to the vessels. B) Multinodular myxoid spindle cell tumor arising from the pancreas (40xH&E). C) Vascular involvement/infiltration
(100xH&E). D) Intersecting bundles of bland spindle cells with eosinophilic cytoplasm and hyperchromatic nuclei (200xH&E)
E) Transition to high-grade areas (200xH&E) F) High-grade areas with prominent nuclear pleomorphism and hyperchromasia
(200xH&E) G) High mitotic activity is readily seen (400xH&E). Neoplastic cells were positive for SMA (H, 200x), desmin (I, 200x) and
EBER (J, 400x)
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|Figure 2: Lung and liver metastases of EBV-positive LMS Case #1 showing similar morphology and immunophenotype.
The second case was a 55-year-old female with a 7x5x5 cm
soft tissue mass located in the chest wall beneath the right
breast and infiltrating the right anterior parts of the 9-10th
ribs. The patient underwent marginal surgical excision. The
tumor was vaguely nodular with myxoid areas and composed
of long intersecting fascicules composed of pleomorphic spindle
cells with a mitotic activity of 20/10 HPF. Bone and pleural
invasion and focal areas of necrosis were also present. Neoplastic
cells diffusely expressed SMA, desmin, and h-caldesmon,
while pan-keratin (AE1/3) was negative (Figure 3). She
received adjuvant chemotherapy and was lost to follow-up
after 13 months.
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|Figure 3: EBV-positive LMS Case #2: A) Multinodular tumor composed of prominent myxoid and solid areas with a collagenous
background (40x H&E). B) Cellular areas resembling fibrosarcoma (100xH&E) C) Higher magnification shows spindle cells with relatively
bland, cigar-shaped nuclei and contrasting brisk mitotic activity (200xH&E). D) Other areas with prominent nuclear pleomorphism
(200xH&E). Neoplastic cells diffusely expressed SMA (E, 100x), desmin (F, 100x), h-caldesmon (G, 100x), and EBER (H, 100x). I) EBV
real-time PCR assay was positive with a cycle threshold (Ct) value of 31.54.
EBV is involved in the pathogenesis of various tumors: 1)
carcinomas, either prevalently such as nasopharyngeal carcinoma,
or only certain subsets such as gastric carcinomas; 2)
a wide range of lymphoproliferative disorders such as Burkitt
lymphoma, Hodgkin lymphoma, and nasal type T/NK
cell lymphoma to name a few; 3) some rare tumors such as
Epstein-Barr virus-associated smooth muscle tumor (EBVSMT)
and inflammatory pseudotumor-like follicular dendritic
cell tumor (IMT-FDCT)(8). Among these, EBV-SMT is a
relatively uncommon neoplasm associated with immunodeficiency.
It has been described in patients infected with human immunodeficiency virus (HIV/AIDS), in the posttransplant
setting and those with congenital immunodeficiency. The
incidence rate of post-transplant EBV-SMT is reported as
1-2% in kidney transplant patients 3
. Various anatomic sites, including the retroperitoneum and soft tissues, can be affected
by EBV-SMT with a tendency to multifocal involvement. On
morphological grounds, tumors are usually indistinguishable
from an ordinary low-grade LMS or leiomyoma; however, the presence of variable numbers of intratumoral lymphocytes
and EBER positivity are the unique defining features of
this tumor 4,6
. Although many EBV-SMT cases have been
reported especially after the rise of HIV/AIDS, no studies have
investigated the incidence of EBV in common LMS. In our
study, 2 of 93 LMS were found positive for EBV and both of
them were extra-uterine with an overall incidence of 2.2% of
total LMS and 5% of the extra-uterine LMS. Neither of the
patients had experienced immunosuppression at the time of
presentation. These cases could be classified as either EBVSMT
or “EBV-positive LMS”; however, even with the small
number of cases, the term “EBV-positive LMS” sounds better
since our 2 cases were high-grade sarcomas with prominent
pleomorphism occurring in immunocompetent patients,
lacked lymphocytes, and had a poorer prognosis than EBVSMT
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|Table II: Clinicopathological comparison between “EBV-SMT” and the proposed term “EBV-positive LMS”.
Apart from commonly seen TP53, RB1 and PTEN alterations,
genomic and transcriptomic investigations have uncovered
three specific subtypes LMS that likely develop from distinct
lineages of smooth muscle cells: 1) Dedifferentiated LMS with
myogenic differentiation and high immune cell infiltration, 2)
Tumor arising in the abdomen or extremities with vascular smooth muscle phenotype, low mutational burden, and a better
prognosis, and 3) Tumors primarily of gynecological origin
with dystrophin alterations 9,10. One of our patients (case
#1) is more likely to correlate with LMS subtype 2, having
features such as intraabdominal tumor of probable vascular
origin, lack of prominent inflammatory cell infiltration, and a
relatively smoldering clinical course. Gynecological LMS has
been shown to be molecularly different from soft tissue LMS.
Along those lines, we have shown that EBV does not seem
to play any role in the etiology of the uterine LMS of immunocompetent
patients, as none of the 55 uterine LMS cases
was positive for EBER. In the literature, there is only one case
report in which EBV was demonstrated in the uterine LMS of
a 40-year-old woman one year after bilateral lung transplantation
due to sarcoidosis 11. Given the fact that EBV-SMT can
occur in many locations such as blood vessels, liver, spleen,
colon, and lung in the setting of immunosuppression, it is not
surprising to encounter a case in the uterus.
The pathogenesis and latency type of EBV-SMT is not wellknown.
MYC overexpression and activation of the mTOR/
Akt pathway are considered the main events in EBV-derived
smooth muscle proliferation 12. There are controversial data on the expression of LMP1 and other EBV-related proteins in
EBV-SMT 8. The complete absence of LMP1 in all presented
cases suggests that type I latency might be involved in EBVSMT
and EBV-positive LMS. However, previously reported
del-LMP1 variant and EBNA2 expressions or a possible
LMP2 might also be involved in these tumors, suggesting type
II or more likely type III latency similar to post-transplant
lymphoproliferative disorders 1,13. The event underlying
multifocality (whether metastatic spread or multifocal occurrence)
has been addressed by Deyrup et al. by stating that the
separate nodules in a given patient are clonally distinct, therefore
representing different tumors from multiple/multifocal
infectious events rather than metastasis 1.
EBER is recommended before diagnosing any smooth muscle
tumors seen in patients who have a history of immunodeficiency
2. Regarding our findings, we also recommend EBER
testing in diagnosing smooth muscle tumors of non-uterine
locations, regardless of the grade of tumor and immune status
of the patient. Although the investigation of EBV in leiomyosarcoma
in immunocompetent patients seems to be a nonsense
and money consuming practice, it might also have a
predictive value in the management of treatment. Rapamycin,
an mTOR inhibitor, has been reported to be effective on EBVpositive
B-cell lymphomas by inhibiting cell cycle 14,15 and
post-transplant EBV-SMT 3.
The differential diagnosis of classical EBV-SMT includes
Kaposi sarcoma, mycobacterial spindle cell pseudotumor,
and myopericytoma to some extent, as these tumors have a
relatively low-grade morphology and are seen in immunosuppressed
individuals. However, EBV positive LMS typically
presents in immunocompetent patients and shows high-grade
morphology. The differential diagnosis is therefore different
from EBV-SMT and includes common differentials of LMS,
such as GIST, dedifferentiated liposarcoma, pleomorphic sarcoma,
malignant peripheral nerve sheath tumor, as well as
some other EBV-related conditions, particularly inflammatory
pseudotumor-like follicular dendritic cell tumor (IMTFDCT).
IMT-FDCT is regarded as a subgroup of follicular
dendritic cell sarcomas and commonly presents as a solitary,
indolent, painless mass located at extranodal sites such as the
spleen, liver, and tonsils. Histologically, it consists of storiform
fascicles of plump spindle cells with vesicular nuclei and
accompanying prominent inflammatory cells and expresses
SMA along with dendritic markers, such as CD21, CD23,
and CD35, but desmin or h-caldesmon are consistently negative.
An answer to the prompt question “Are there any other
sarcomas positive for EBV?” is partially given by Lenze et al., as there were no EBV-positive cases in 44 synovial sarcomas
studied 16. The presence of EBV in other types of sarcomas
remains to be elucidated.
In conclusion, we have identified the presence of EBV in a
subset of non-uterine LMS in immunocompetent patients,
for which we proposed the term “EBV-positive LMS” due to
the presence of clinical and pathological features distinct from
EBV-SMT classically seen in immunosuppressed patients.
This study was supported by BAGEP-2014, the Academy of Science,
Conflict of Interest
No conflict of interest
Concept: KK, Design: HA, KK, Data collection or processing:
HA, AA, GG, KK, Analysis or Interpretation: HA, AA, GG, KK,
Literature search: HA, KK, Writing: HA, AA, KK, Approval: HA,
AA, GG, KK.
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