To review the characteristics of paraspinal SS, provide insights to prevent misdiagnosis, and comprehensively analyze treatment advancements; we conducted a thorough case review. The literature review utilized two major databases, PubMed (https://pubmed.ncbi.nlm.nih.gov/) and Web of Science (https://www.webofscience.com/wos/woscc/basic-search), searching relevant English-language articles from 2004 to 2024. The search keywords were "spine," "paraspinal," "synovial sarcoma," and "case report." A total of 59 articles related to paraspinal SS were retrieved, with 28 meeting the criteria of "primary paraspinal synovial sarcoma." These 28 cases were arranged chronologically and summarized in a table, detailing each patient's age, gender, symptoms, imaging findings, misdiagnoses, metastasis status, tumor type, location, treatment methods, treatment outcomes, and follow-up duration (Table 1) [4–31].
Table 1
Literature review of 28 paraspinal synovial sarcoma cases, arranged by year.
Authoes & Year
|
Age
(years)
/sex
|
Symptom
|
Radiology
|
Misdiagnosis /Metastasis
|
Type/
Location
|
Treatments
|
Outcome
/ Follow-up(months)
|
Wang et al. [6]
2022
|
16/F
|
Upper back pain, paraparesis,
hypalgesia, bilateral lower limb numbness, and disabled walking.
|
CT: Compression fracture and right-sided soft tissue mass
MRI: Evident patchy calcification at the edge of the vertebral body and spinal cord compression
|
N0/No
|
M/
T7-T8
|
Surgery
Radiotherapy
Chemotherapy
|
Alive/8
|
Zhang et al. [7]
2021
|
13/F
|
Pain in the left lower limb.
|
CT: Large mixed-density tumor in the left abdominal cavity at the thoracic level and extensive calcifications in the spinal canal and paraspinal region.
|
N0/No
|
M/
T11-L4
|
Surgery
Chemotherapy
|
Alive/4
|
Feng et al. [32]
2020
|
56/F
|
Low back pain.
|
CT: Lungs: Multiple pulmonary nodules.
L2: Bony erosion of L2 vertebra, spinal canal stenosis.
|
N0/No
|
M/
L2
|
Surgery
Radiotherapy
|
Alive/INA
|
Zimelewicz Oberman
et al. [9] 2020
|
62/M
|
Progressive thoracic pain,
gait weakness, sudden paraplegia, and urinary/bowel dysfunction.
|
CT: Thoracic paravertebral mass, cord compression.
MRI: Space-occupying lesion, osteolytic lesions, increased FDG uptake through the axial spine and appendicular skeleton.
|
N0/No
|
B/
T5-T9
|
Radiotherapy
Chemotherapy
|
INA/INA
|
Alshehri
et al. [10] 2020
|
12/F
|
Lower-mid back pain extending to the left anterior thigh, increasing lumbar mass.
|
CT: Left paraspinal soft-tissue mass from T12 to L4 Level.
|
N0/No
|
M/
T12-L4
|
Surgery
Radiotherapy
Chemotherapy
|
Alive/12
|
Subramanian et al. [11] 2020
|
46/F
|
Midback pain, bilateral lower limb weakness.
|
PET-CT、MRI: Dumbbell-shaped thoracic spinal cord tumor at T7-T8 level with erosion of lamina and pedicle
|
Nerve sheath tumour/No
|
M/
T7-8
|
Surgery
Radiation
|
Alive/12
|
Najib et al. [12]
2018
|
44/M
|
Chronic lower back pain, bilateral groin radiation.
|
CT: Spine: A sclerotic and lytic lesion
Both lungs: Multiple bilateral pulmonary nodules along with mediastinal and hilar lymphadenopathy
|
N0/No
|
M/
T12
|
INA
|
INA/INA
|
Shah et al. [4]
2018
|
40/M
|
Shoulder pain, bilateral arm radiation, progressive quadriparesis, back bulge, urinary incontinence.
|
CT: Large intradural-extramedullary mass with neural compression and paraspinal extension from C5 to D5.
|
Spinal tuberculosis /Both lungs
|
M/
C5-D5
|
Surgery
Radiation
|
Alive/24
|
Guo et al. [5]
2016
|
10/M
|
Progressive back pain, low-grade fever, acute paraplegia.
|
MRI: Extradural gadolinium-enhancing lesion at T9-10.
|
Inflammatory abscess/No
|
INA/
T9-T10
|
Surgery
Radiation
|
Alive/6
|
Yang et al. [13]
2016
|
20/M
|
One-month history of left-sided hypoesthesia.
|
MRI: Intramedullary mass with peritumoral edema at C2.
|
N0/No
|
M/
C2
|
Surgery
|
Die/1
|
Chen et al. [14]
2016
|
20/F
|
Low back pain,
left low back swelling,
recent paraparesis.
|
CT: Left paraspinal mass with bone erosion,
T12-L2 spinal cord compression.
MRI: Heterogeneous mass with cystic and
solid features.
|
N0/No
|
M/
T12-L2
|
Surgery
Radiation
|
INA/INA
|
Cao et al. [15]
2014
|
26/M
|
Low back pain.
|
CT: Spine: T7 bony erosion, no soft tissue mass.
Both lungs: Multiple lung nodules with clear boundaries.
MRI: The tumor entered the canal and pressed against the cord
|
N0/No
|
B/
T7
|
Surgery
Radiotherapy
Chemotherapy
|
Alive/12
|
Kim et al. [16]
2014
|
29/M
|
Neck mass with right arm pain, limited ROM.
|
CT: Lobulated calcified paravertebral space mass at the right occipitocervical junction on CT Imaging
|
N0/No
|
B/
C2-C3
|
Surgery
Radiation
|
Alive/24
|
Peia et al. [17]
2013
|
7/F
|
Progressive anterolateral Knee pain with gait disturbances
|
MRI: Oval, enhancing lesion at L4-5, left neural foramen widening.
|
Schwannoma /No
|
B/
L4-L5
|
Surgery
Chemotherapy
|
Alive/60
|
Kim et al. [18]
2013
|
17/M
|
Diving-related posterior neck pain and bilateral upper limb numbness.
|
X-ray: C3 vertebra expansile osteolytic lesion with cortical thinning.
MRI: Vertebral epidural mass in C3 with extraosseous extension and enhancement
|
N0/No
|
M/
C2–C3
|
Surgery
Chemotherapy
|
INA/INA
|
Yonezawa
et al. [19] 2012
|
11/F
|
Low back pain.
|
MRI: An intradural, extramedullary, and uniformly enhancing mass that extended from L3 to L4
|
N0/No
|
M/
L3 - L4
|
Surgery
Radiation
|
Alive/60
|
Naphade
et al. [20] 2011
|
14/M
|
Shoulder pain with thumb and index finger radiation, right limb weakness/wasting.
|
MRI: Extramedullary oval lobulated mass lesion in C6-C7 intervertebral foramen with nerve root compression.
|
N0/No
|
M/
C6-C7
|
Surgery
|
Alive/60
|
Zairi et al. [21]
2011
|
36/M
|
Neck mass with pain.
|
CT: Left lung nonspecific node.
MRI: Posterior cervical soft tissue tumor.
|
N0/Lung
metastases
|
B/
C1-C2
|
Surgery
Radiation
|
Die/72
|
Foreman
et al. [22] 2011
|
29/M
|
Posterior cervical spine muscle discomfort/pain after weight lifting.
|
CT: Cystic mass at C4-C5, non-enhancing.
MRI: Septated kidney bean-shaped mass with high signal.
|
N0/No
|
B/
C3-T2
|
Surgery
Radiotherapy
Chemotherapy
|
Alive/72
|
Liu et al. [23]
2010
|
12/M
|
Sacral mass with progressive increase is associated with lameness, intermittent bilateral leg pain, and voiding dysfunction.
|
CT: S3-C1 vertebral involvement with tumor calcification.
MRI: Large enhancing sacral lesion below S2.
|
N0/Chest
|
B/
S3-S2
|
Surgery
Radiotherapy
|
Die/21
|
Koehler
et al. [27] 2009
|
60/M
|
Abdominal pain with radiation to back, dyspnea on exertion, increased pain on standing
|
CT: Right paraspinal mass, T9 vertebral lysis.
MRI: Large right-sided paraspinal mass, eighth and ninth ribs.
|
N0/No
|
M/
T7-T10
|
Surgery
Radiotherapy
|
Alive/9
|
Barus et al. [26]
2009
|
14/F
|
Chronic lumbar pain, associated neurologic symptoms, and a palpable mass.
|
CT: Soft-tissue mass, Lumbar spine, local bone erosion, no metastasis/adenopathy.
MRI: Large enhancing lesion, Lumbar spine, spinal canal, epidural involvement, neural compression.
|
N0/No
|
M/
L2-L5
|
Surgery
Radiotherapy
Chemotherapy
|
Alive/69
|
Ravnik et al. [25]
2009
|
32/M
|
Rapidly progressing paraparesis.
|
MRI: Intraspinal epidural tumor, significant paravertebral/
retroperitoneal extension,
large extraspinal component.
|
N0/No
|
M/
T12-L1
|
Surgery
Radiotherapy
Chemotherapy
|
Die/12
|
Mullah-Ali
et al. [24] 2008
|
14/F
|
History of neuroblastoma radiation therapy, intermittent knee pain post-fall, pelvic tilt, persistent night back pain, left leg weakness.
|
CT: Left paraspinal mass, L3-L4 neural exit foramen, marked narrowing of the spinal canal.
MRI: Multilobulated heterogeneous mass, L3-L4 level, intraspinal extension.
|
N0/Pulmonary metastases
|
M/
L3-L4
|
Surgery
Radiotherapy
Chemotherapy
|
Alive/6
|
De Ribaupierre et al. [28] 2007
|
11/F
|
Cervicobrachialgia, weakness in the right arm.
|
MRI: Enhancing heterogeneous intradural mass, right C6-C7 foramen.
|
N0/No
|
M/
C6-C7
|
Surgery
Radiotherapy
Chemotherapy
|
Die/60
|
Greene et al. [29]
2007
|
11/F
|
Back pain, radiculopathy.
|
MRI: Intradural masses at C6, T2, T5, T8, and L1 levels; additional nodules of enhancement at L2-L4.
|
N0/Leptomeningeal metastasis
|
M/
L2-L4
|
Surgery
Radiotherapy
Chemotherapy
|
Die/14
|
Sakellaridis
et al. [30] 2006
|
36/F
|
Experiencing low back pain, walking difficulties, or urinary incontinence.
|
MRI: Recurrent epidural tumor, L2-L3 level, attached to dura mater.
|
N0/Brain
Lungs
Spinal metastases
|
M/
L2-L3
|
Surgery Radiotherapy
|
Die/18
|
Suh et al. [31]
2005
|
44/M
|
Right-sided sciatica.
|
MRI: Right epidural, paravertebral mass, widened L4-L5 neural foramen, eroded L5 articular process,
|
N0/No
|
B/
L4-L5
|
Surgery
Radiotherapy
|
Alive/5
|
M: male, F: female, B: biphasic, M: monophasic, INA: information not available, ROM: range of motion |
In all 28 reported cases, the average patient age was 26.5 years, with a standard deviation of 16.53 years, indicating that paraspinal SS predominantly affects young individuals. The age range was broad, spanning from 7 to 62 years, showing that this tumor can impact almost any age group. Males were slightly more affected than females, but the gender difference was not particularly significant.
The clinical features of paraspinal SS present a range of symptoms closely related to the tumor's location and size. Patients often first experience localized pain in the tumor area, which may progressively worsen over time, prompting them to seek medical attention. As the tumor grows and compresses surrounding structures, patients may develop neurological deficits such as limb weakness, numbness, sensory reduction or abnormalities, and even gait disturbances, affecting daily walking. These symptoms are typically associated with nerve root compression. In some cases, prolonged neurological impairment can lead to muscle atrophy, especially in the affected limb. Additionally, bladder and bowel dysfunction may occur if the tumor compresses the lower spinal cord. Severe spinal cord compression can result in sudden paralysis. Rare symptoms like fever may also occur, overlapping with infectious diseases and necessitating comprehensive evaluation based on the patient's overall clinical presentation.
Imaging characteristics of paraspinal SS typically include a tumor in the epidural space of the spinal cord, which may appear as a paraspinal soft tissue mass on CT scans, often showing mixed density with shapes such as patchy, dumbbell-shaped, multilobulated, or oval. Vertebral compression fractures, bone destruction, and erosion of the vertebral body may be observed, sometimes with patchy calcifications along the vertebral margins. The tumor may compress the spinal cord or nerve roots, causing deformation or displacement. On MRI, SS shows high signal intensity on T1-weighted images and intermediate signal intensity on T2-weighted images, possibly due to hemorrhage. SS can exhibit a "triple signal intensity" pattern: high, intermediate, and low signals. Post-contrast MRI typically shows heterogeneous enhancement. Tumors often erode the vertebral bones, leading to cortical disruption. Additionally, the tumor may compress adjacent blood vessels and neural structures, causing displacement or signal changes. In advanced cases, distant metastases, such as to the lungs or other bones, may occur, with the lungs being the most common site. Tissue biopsy is considered the gold standard for determining the tumor's nature. SS is a diverse malignant tumor with varying subtypes and biological behaviors. Histologically, the tumor can be biphasic or monophasic, with monophasic cases (20/28) being more common than biphasic cases (8/28) in paraspinal SS. Late-stage paraspinal SS metastasis to other sites significantly impacts patient prognosis. The most common metastatic site is the lungs, followed by intravertebral metastasis. Although rare, leptomeningeal metastasis can occur in paraspinal SS patients, leading to a poor prognosis and shorter survival time.
Comprehensive treatment of paraspinal SS primarily involves radical surgery supplemented with local radiotherapy and chemotherapy. In our case review, the majority of patients (26/28) underwent surgical treatment. Surgical resection is the primary treatment choice for SS, especially when complete or near-complete tumor removal can be achieved, leading to better short-term outcomes. However, not all cases can achieve complete tumor resection, and there is a high risk of recurrence. In such cases, radiotherapy is an important adjunctive treatment, reducing the risk of local recurrence or treating tumors that are not accessible surgically. When metastasis occurs, chemotherapy plays a crucial role in SS treatment, with cyclophosphamide and adriamycin being the first choices.
SS is a rare and complex disease that is prone to misdiagnosis due to its symptoms and imaging characteristics overlapping with many other conditions. In our review, we found that it was often misdiagnosed as a nerve sheath tumor, spinal tuberculosis, inflammatory abscess, or schwannoma [4, 5, 11, 17]. These conditions can cause spinal cord compression, localized pain, and neurological deficits, which overlap with the manifestations of paraspinal SS, increasing the difficulty of diagnosis. Improving the first diagnosis rate and surgical intervention in the early stages of tumor development is often a more ideal and effective treatment method. As shown in this case, the patient's tumor was initially mistaken for a paraspinal cold abscess caused by spinal tuberculosis and was treated with an anti-tuberculosis regimen for one month at an outside hospital. During this period, the patient missed the optimal treatment window and developed extensive lung metastasis.
We analyzed the reasons why the patient was misdiagnosed as lumbar tuberculosis with paraspinal tuberculosis abscess. The patient's test results from the outside hospital were weakly positive for anti-tuberculosis antibodies, and the magnetic resonance examination suggested that the L4-S1 intervertebral disc had been infringed upon. The patient also had a history of irregular fever during hospitalization in the outside hospital, and the combination of test results and findings justified a certain degree of lumbar tuberculosis suspicion. However, Mycobacterium tuberculosis was not detected in the patient's sputum smears, and her MRI after admission to our hospital showed a mass-occupying lesion in the left lumbar psoas muscle, with clear boundaries, uneven signals within the mass, and outward displacement of the left lumbar psoas muscle. Additionally, a weakly positive anti-tuberculosis antibody does not necessarily indicate current tuberculosis; it could be a false positive or indicate past tuberculosis that has resolved. Therefore, the patient's diagnosis was not clear, making a puncture biopsy necessary to clarify the pathological diagnosis when the patient only experienced localized low back pain without causing lower extremity symptoms. Unfortunately, the patient did not undergo a biopsy at the initial stage of consultation, and we hypothesized that the reason was the use of anti-tuberculosis drugs at the initial stage to limit the development of the tuberculous abscess according to the principle of paraspinal tuberculosis treatment and that performing a puncture biopsy when the infection was not under control might result in undesirable consequences, such as spreading of the infection.
Our patient experienced rapid, extensive lung metastasis due to early misdiagnosis, missing the optimal time for surgical treatment. We can predict a short survival time for such cases. We hope that by sharing this case, we can draw attention to this type of malignant tumor with relatively low incidence so that you can be prepared to make differential diagnoses, shorten the diagnostic period, and provide early surgical and pharmacological interventions to maximize the survival time and quality of life for your patients when encountering such cases.