Surgical Science, 2011, 2, 62-65
doi:10.4236/ss.2011.22013 Published Online April 2011 (
Copyright © 2011 SciRes. SS
Cystic Synovial Sarcoma of the Lower Extremity: A Case
Report and Review of the Literature
Jenifer Heckman, Agnes Witkiewicz, Adam C. Berger
Departments of Surgery and Pathology, Kimmel Cancer Center, Thomas Jefferson University,
Philadelphia, PA 19107
E-mail: adam.berger@jefferso
Received January 13, 2011; revised January 19, 2011; accepted February 15, 2011
Synovial sarcomas are rare tumors which most often present in the distal extremities of young adults and
children. There are unique clinicopathologic features of this tumor which lend themselves to multidiscipli-
nary treatment and translational research. We present a case of a primarily cystic synovial sarcoma and pro-
vide a thorough review of the available literature.
Keywords: Synovial Sarcoma, Multidisciplinary Treatment, Radical Resection
1. Introduction
Synovial sarcoma is a unique subtype of soft tissue sar-
coma with a propensity for developing in the extremities
of young adults. They have a characteristic histopathol-
ogy and molecular genetic profile and are deemed high
grade tumors. We report a case of a patient with a cystic
synovial sarcoma involving the lower extremity and a
review of the literature, with a focus on diagnosis, prog-
nostic indicators, recent developments in management,
and the future direction of therapy.
2. Case Report
A 49-year-old Caucasian female presented initially for
evaluation of a left posterior thigh mass. The patient de-
scribed a history of a pulled muscle six months prior
followed by tightness in the back of her thigh. In the
couple of months preceding presentation, the mass
evolved, increasing in size and causing discomfort and
pain. The patient noted difficulty with activity and bend-
ing her knee secondary to increased pain. The patient
also reported a several month history of progressive fa-
tigue. Physical examination revealed a solid, mobile
mass in the posterior thigh compartment. The mass was
slightly tender to the touch with no abnormalities in the
overlying skin.
Radiographic evaluation of the left knee was normal.
Ultrasound evaluation revealed the presence of a mass.
MRI with and without intravenous contrast demonstrated
a complex, predominantly cystic mass measuring 6.8 ×
7.2 × 9.7 cm on the posterolateral aspect of the mid-thigh,
deep in the muscle compartment (Figure 1). The mass
was located in the region of the sciatic nerve and inferior
gluteal vessels and found to medially displace the
semimembranosus and semitendinosus muscles and
posteriorly displace the long head of the biceps femoris
head and encase the short head of the biceps femoris
muscle. Breakdown products from prior hemorrhage
were noted as well as inflammatory changes in the
adjacent fat at the superior and inferior aspects of the
mass. At this time, unable to specifically characterize the
mass and with a differential including malignancy,
biopsy was recommended. Due to the cystic nature of the
mass, tissue diagnosis of the mass was obtained via exci-
sional biopsy.
Following wide local surgical excision, where the
mass was dissected free from the surrounding muscle and
sciatic nerve with its pseudocapsule preserved, pathology
revealed a 230-gram mass, measuring 9.0 × 7.5 × 6.0 cm,
surfaced by glistening red-tan membranous tissue. Sec-
tioning showed multiple cysts filled with hemorrhagic
fluid. Findings were consistent with synovial sarcoma
with cystic change, measuring 9 cm and focally extend-
ing <0.1 cm from the margin. Immunohistochemistry
was significant for stains positive for EMA, bcl-2, Ck5/6,
and negative for CD34 (Figure 2). With negative mar-
gins surgically achieved, re-excision was foregone due to
proximity to the sciatic nerve and high rate of systemic
(a) (b)
Figure 1. Cross-sectional MRI images reveal mostly cystic mass in the posterior compartment of the thigh on T1-weighted (a)
and T2-weighted (b) images.
(a) (b)
(c) (d)
Figure 2. Histologic examination of synovial sarcoma. (a) shows 10x magnification using standard H&E staining; (b) shows
40x magnification with H&E staining as well; (c) shows positive staining under 40x magnification for bcl-2; and (d) reveals
ositive immunohistochemistry staining for smooth muscle ac tin. p
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The patient was referred to a medical oncologist and
radiation oncologist for additional evaluation and treat-
ment. A staging work-up, including a chest radiograph
and computed tomography (CT) scan, demonstrated
prominent bilateral axillary lymph nodes but no evidence
of metastatic disease. Staging identified the lesion as a
T2b N0 M0 synovial cell carcinoma. Due to the lesion
size, the patient was determined to be at high risk for
recurrence. As such, the patient was subsequently treated
with a combination of adjuvant chemotherapy and radia-
tion. Four cycles of ifosfamide and doxorubicin, which
were tolerated well, were initiated prior to radiation
3. Discussion
Synovial sarcomas are rare malignant tumors historically
regarded as high grade malignancies with significant
metastatic risk. Synovial sarcoma accounts for 6-10% of
all adult soft tissue sarcomas, rendering it the fourth most
common type of sarcoma. Despite its name, this tumor is
uncommon in joint cavities, instead occurring primarily
in periarticular regions of extremities and often associ-
ated with tendon sheaths, bursae, and joint capsules.
Principally affecting young adults aged 15-40 years, with
the median age of patients in the third decade of life,
synovial sarcoma most commonly presents as a palpable,
deep-seated swelling or mass associated with pain or
tenderness. The extremity is the most common site of
primary disease, and the tumor tends to grow insidiously,
frequently delaying diagnosis and therapy. [1,2]
Definitive diagnosis is often deferred until histopa-
thologic examination of the surgical specimen upon re-
section. Pre-operative radiographs may exhibit calcifica-
tions within the tumor. Synovial sarcomas frequently
appear as round or oval, lobulated, in close association
with a large joint, and without involvement of the under-
lying bone. Computed tomography (CT) and magnetic
resonance imaging (MRI) may be utilized in further elu-
cidating the site of origin and extent of the mass. Syno-
vial sarcoma represents a malignancy of two morpho-
logically distinct cell types that form a characteristic bi-
phasic pattern: epithelial cells and fibrosarcoma-like
spindle cells. Synovial sarcomas may be classified into
biphasic variant, monophasic fibrous variant, monopha-
sic epithelial variant, and poorly differentiated variant.
Large studies, however, have not demonstrated his-
tologic type to be of prognostic or therapeutic signify-
cance. [3] Immunohistochemical stains further aid in the
diagnosis of synovial sarcoma, the most useful of which
are epithelial markers, including pankeratin, CAM 5.2,
and EMA, as identified in our patient. These markers are
less apparent in the spindle cell component of these tu-
mors, leading to the distinctive patchy staining pattern
found in synovial sarcoma. In addition, in accordance
with our findings, synovial sarcoma stains positively for
bcl-2 and is consistently negative for CD34. Cytogenetic
studies also indicate the presence of a translocation be-
tween chromosomes X and 18, t(X; 18) (p11.2; q11.2), in
nearly all (>90%) cases of synovial sarcoma. This char-
acteristic translocation involves the SYT gene on chro-
mosome 18 and the SSX1 and SSX2 genes, located on
the X chromosome, and leads to the creation of abnormal
fusion proteins. [4]
Synovial sarcoma traditionally carries a poor progno-
sis. [3] In a retrospective analysis of synovial sarcoma in
patients of all ages, Ferrari et al. [5] determined survival
rates to vary significantly, measuring 5-year event-free
survival to be 37 % for the study cohort as a whole, with
the rate varying with age (66%, 40%, and 31% for pa-
tients age 16, 17-30, and >30 years, respectively).
0Large tumor size has been consistently shown to be
related to the progression to distant metastasis and de-
creased disease specific survival, and most studies dem-
onstrate that prognostic indicators of distant recurrence
parallel survival. [4] In a multivariate analysis of prog-
nostic factors, Lewis et al. [6] demonstrated tumor size
5 cm and invasion of bone and neurovascular structures
to be the only independent adverse predictors of distant
recurrence and mortality.
Complete surgical resection remains the foundation of
treatment for synovial sarcoma. Despite the frequent
close proximity of the tumor to neurovascular structures,
en bloc resection of the tumor is standard and these
structures are usually spared. Adequate margins require
that the resected specimen be tumor free at the margins,
preferably with a margin of normal tissue. There is no
role for non-curative surgery. [4] Achieving adequate
surgical margins, however, must be balanced with
maximal preservation of function and minimal morbidity.
[3] Surgery is also the mainstay of treatment for locally
recurrent disease. The role of surgery in treating metas-
tatic synovial sarcoma is less well defined and limited to
selected patients based on disease extent, length of dis-
ease-free interval, and response to systemic chemother-
apy. [4]
Beyond surgery, the optimal therapeutic approach to
synovial sarcoma has not yet been definitively estab-
lished. However, prognosis is poorest in patients treated
only with local excision with inadequate margins and no
adjunctive therapy, with recurrence rates recorded as
high as 70-83%. [2] As in the management of other soft
tissue sarcomas, there is a role for adjuvant radiation
therapy. Although good local control can be accom-
plished through surgery and radiation therapy, distant
metastasis remains the limiting factor with regard to the
survival of patients with synovial sarcoma. [4] Despite
adequate surgical resection, Lewis et al. [6] noted that
distant metastasis developed in almost 40% of patients
by 5 years, suggesting the need for adjuvant systemic
therapy. Synovial sarcoma is known to be particularly
chemosensitive. [4] Ferrari et al. [5] demonstrated the
benefit of chemotherapy, showing that among patients
with surgically resected tumors, 5-year metastatic-free
survival rate in those receiving chemotherapy was 60%
as compared to 48% in those who did not. The outcome
advantage was noted particularly among those with
high-risk synovial sarcoma (tumor size >5 cm), leading
investigators to conclude that all patients with tumors >5
cm should be treated with chemotherapy. Multiple stud-
ies have revealed the utility of ifosfamide-based chemo-
therapy (+/– doxorubicin). In fact, it is the treatment of
choice for patients with metastatic synovial sarcoma.
Recent studies have shown ifosfamide-based therapeutic
regimens to be effective in increasing disease-specific
survival in patients with 5 cm, primary, extremity
synovial sarcomas. [4]
Recent studies also indicate a role for sentinel lymph
node biopsy in synovial sarcoma. Lymph node metasta-
sis in soft tissue sarcoma in an extremity is considered to
herald poor outcome. However, current literature sug-
gests that complete surgical resection of involved lymph
nodes may improve survival. [7] While the lung remains
the most frequent site of metastasis, regional lymph node
metastases have been demonstrated in 6-14% of synovial
sarcoma cases. In a retrospective analysis of sentinel
node biopsy in a cohort of eleven patients with synovial
sarcoma, Tunn et al. [8] identified at least one node in
each patient, and no patients developed complications
post-procedure. Of a total of 15 sentinel nodes identified,
only one was positive and 14 were negative.
4. Conclusion
In summary, we report herein the case of a woman with a
9 cm synovial sarcoma of the left lower extremity. Espe-
cially with such large tumor size, such a diagnosis is
typically associated with a poor prognosis. However,
future investigations hold promise. Surgery remains the
mainstay of treatment, but it is clear that obtaining more
definitive data concerning the clinical management of
this tumor, including the utility of radiation and chemo-
therapy and the possible development of more targeted
therapeutic interventions, is warranted.
5. References
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