Synovial sarcoma: Magnetic resonance and computed tomography imaging features and differential diagnostic considerations

Diagnostic challenges in imaging and immunohistopathological profiles in extraskeletal osteosarcoma

This correspondence addresses the article published by Nie et al. titled "Primary extraskeletal osteosarcoma of sigmoid mesocolon: a case report and a review of the literature". Their report highlighted an extremely rare case of extraskeletal osteosarcoma (EO) in the sigmoid mesocolon that was diagnosed through imaging and histopathological findings. Diagnosing EO has certain challenges; one of them being the lack of characteristic image findings of EO and the other being the lack of appropriate immunohistochemical (IHC) markers in the histopathological findings. Recently, special AT-rich sequence-binding protein 2 (SATB2) has been proposed as an IHC marker for osteoblastic differentiation; however, it has low specificity. Some cases of EO may show findings such as mouse double minute protein 2 expression and deletion of histone H3 lysine 27 trimethylation (H3K27me3), which are similar to those of other soft tissue sarcomas. Therefore, it is essential to consider other soft tissue sarcomas, especially dedifferentiated liposarcoma, before the accurate diagnosis of EO.

A rare case report of omental synovial sarcoma complicated hemoperitoneum and literature review

BACKGROUND

Synovial sarcoma is a rare malignant soft tissue tumor originating mainly in the extremities and usually related to the joint capsule, tendon sheath, or synovial capsule. Only a few cases of synovial sarcoma arising in the abdomen, particularly the omentum, have been reported. We presented a case of omental synovial sarcoma and reviewed 7 cases of this disease.

CASE PRESENTATION

A 37-year-old man presented to the hospital with abdominal pain and distension for 2 months. A computed tomography scan revealed a massive heterogeneous low attenuation mass with amorphous solid components between the stomach and colon with suspected hemoperitoneum. The patient underwent surgery, and the pathological result demonstrated a greater omentum biphasic synovial sarcoma. Chemotherapy was administered with a good response. He has no signs of recurrence during 3 years of follow-up. Among 7 cases of omental synovial sarcoma, the mean age was 42, ranging from 16 to 66 years old with predominantly female (71.4%), tumor size from 9.5 cm to 20 cm. Biphasic synovial sarcoma accounted for 50%. The recurrence rate within one year is high (57.1%).

CONCLUSIONS

Primary omental synovial sarcoma is uncommon and presents with nonspecific clinical symptoms, often leading to potential misdiagnosis with other conditions before surgery. They occur predominantly in females, mainly middle-aged, with a large mass size before presentation. Due to the high recurrence and mortality rate, it needs to be recognized at the early stage.

Comprehensive treatment of primary pelvic synovial sarcoma: A 28-month follow-up case report and review of the literature

Background

Primary synovial sarcoma originating in the pelvis is an extremely rare malignancy, and only a few cases have been reported. Usually, the tumor is detected at an advanced stage, making treatment more difficult. Lacking high-quality research, there are no consensus guidelines for the systemic treatment of the disease.

Case presentation

We admitted a 32-year-old male patient with an MRI suggestive of an 8.2 × 7.7 x 8.9 cm mass in the pelvis with bleeding. After a comprehensive evaluation, the patient underwent surgery, and postoperative pathology suggested biphasic synovial sarcoma. Once the diagnosis was clear, the patient was treated with chemotherapy, radiotherapy, and targeted therapy. Unfortunately, the patient died due to a recurrence of pelvic synovial sarcoma with multiple metastases throughout the body, with a survival period of 28 months.

Conclusion

Synovial sarcoma, a highly malignant soft tissue tumor, and primary intrapelvic synovial sarcoma are even rarer, with a poor prognosis. Ultrasound, Computed Tomography, and MRI can help doctors detect the tumor at an early stage and treat it aggressively, especially with surgical treatment, which can effectively improve the survival rate. Combined with the course of diagnosis and treatment of this case, it is possible to deepen the understanding of primary pelvic synovial sarcoma and discuss appropriate treatment strategies for this rare disease.

Mediastinal monophasic synovial sarcoma with vertebral metastases: A case report

Mediastinal monophasic synovial sarcoma is a rare subtype that often lacks specific imaging characteristics, posing diagnostic challenges. This case report describes a mediastinal monophasic synovial sarcoma with vertebral metastasis, emphasizing imaging findings, differential diagnosis, and pathological features, thereby providing crucial support for accurate diagnosis and treatment planning.

Synovial sarcoma of the viscera (lung and jejunum): a case report

We report the case of a woman nearing 70 years old who was admitted to the hospital with a complaint of "epigastric distension for 1 month". Her main signs and symptoms were progressive abdominal distension and occasional abdominal pain. Computed tomography suggested an abdominal mass. She had a surgical history of synovial sarcoma (SS) of the lungs. After admission, she was diagnosed with jejunal SS following a puncture biopsy and laparoscopic surgery. This disease usually occurs in the soft tissues of the limbs, and it is extremely rare for SS to originate in the jejunum. The morphologic heterogeneity of SS overlaps with other tumors and makes the diagnosis particularly difficult. Imaging studies usually lack specificity; however, measuring multiple immunohistochemical markers can greatly assist in the diagnosis and differential diagnosis of SS. This case not only enriches our understanding of SS and describes a rare site of origin, but also emphasizes the importance and challenges of achieving an accurate diagnosis. Immunohistochemical and molecular biological testing have important roles in the definitive diagnosis, highlighting the need for precise and innovative diagnostic and therapeutic approaches in SS.

An unusual case of retroperitoneal synovial sarcoma with CT, MRI, and F-18 FDG PET/CT findings

Synovial sarcoma, predominantly found in the extremities, rarely occurs in the retroperitoneum. Tumors can often grow to a considerable size before diagnosis, which warrant the critical importance of early detection to minimize morbidity and mortality. While the final diagnosis relies on pathologic examination, imaging plays a crucial role in early detection.

Synovial Sarcoma in the Extremity: Diversity of Imaging Features for Diagnosis and Prognosis

Synovial sarcomas are rare and highly aggressive soft-tissue sarcomas, primarily affecting adolescents and young adults aged 15-40 years. These tumors typically arise in the deep soft tissues, often near the large joints of the extremities. While the radiological features of these tumors are not definitely indicative, the presence of calcification in a soft-tissue mass (occurring in 30% of cases), adjacent to a joint, strongly suggests the diagnosis. Cross-sectional imaging characteristics play a crucial role in diagnosing synovial sarcomas. They often reveal significant characteristics such as multilobulation and pronounced heterogeneity (forming the "triple sign"), in addition to features like hemorrhage and fluid-fluid levels with septa (resulting in the "bowl of grapes" appearance). Nevertheless, the existence of non-aggressive features, such as gradual growth (with an average time to diagnosis of 2-4 years) and small size (initially measuring < 5 cm) with well-defined margins, can lead to an initial misclassification as a benign lesion. Larger size, older age, and higher tumor grade have been established as adverse predictive indicators for both local disease recurrence and the occurrence of metastasis. Recently, the prognostic importance of CT and MRI characteristics for synovial sarcomas was elucidated. These include factors like the absence of calcification, the presence of cystic components, hemorrhage, the bowl of grape sign, the triple sign, and intercompartmental extension. Wide surgical excision remains the established approach for definitive treatment. Gaining insight into and identifying the diverse range of presentations of synovial sarcomas, which correlate with the prognosis, might be helpful in achieving the optimal patient management.

MRI Manifestations of Primary Intraspinal Synovial Sarcoma: A Case Report

Synovial sarcomas represent a highly malignant form of mesenchymal tumors. The incidence of synovial sarcomas in the spinal canal is exceptionally rare and has been scarcely reported.

Teaching Point

Comprehending the magnetic resonance imaging manifestations of intraspinal synovial sarcoma is important to prevent misdiagnosis.

Primary synovial sarcoma on MRI - a case series and review of the literature

Purpose

Simple MRI features are mandatory to facilitate the diagnostics of synovial sarcomas, especially for radiolo-gists outside multidisciplinary sarcoma centres. In this case-series and review, we investigate the main appearance of synovial sarcoma on MRI.

Material and methods

Fifteen histologically proven primary synovial sarcomas who underwent MRI at 2 different sarcoma centres were included in this case series. Patients and their primary synovial sarcomas were examined for age, localization, mean tumour size (in mm), histological grade (G - according to the Fédération Nationale des Centres de Lutte Contre Le Cancer [FNCLCC]), configuration, T2 signal intensity, presence/absence of "triple sign", heterogeneity/homogeneity, borders (well-defined or infiltrative), and intensity of contrast enhancement on MRI. Additionally, a comprehensive literature review to identify observational studies, reviews, and case-reports assessing MRI features of primary synovial sarcoma was performed.

Results

The mean age of the patients was 47.6 years (SD: 17.2). The mean size of primary synovial sarcoma was 59.3 mm (SD: 42). Primary synovial sarcomas were significantly most often multilobulated (n = 12, p < 0.01), heterogeneous (n = 10), and infiltrative (n = 9). Additionally, 3 other primary synovial sarcomas showed the following configurations: ovoid/nodular (n = 2) and fascicular (n = 1). Ovoid/nodular synovial sarcomas were solely depicted as homogeneous with well-defined borders. All tumours showed T2 hyperintense signal and presented with marked contrast enhancement.

Conclusions

Primary synovial sarcomas are mainly multilobulated, heterogeneous, and infiltrative tumours. In minor cases, ovoid/nodular or fascicular configurations occur. Knowing the main appearance of synovial sarcoma can help facilitate the diagnostics of primary synovial sarcomas.

The potential pitfalls of synovial sarcoma mimicking intraneural ganglion cyst: A case report and literature review

INTRODUCTION AND IMPORTANCE

Synovial sarcoma is a rare soft tissue sarcoma (STS) that accounts for 5-10 % of all STS. Synovial sarcoma of the peripheral nerve is very rare, with only 26 cases reported in the literature. Hence, this case report describes an unusual presentation of synovial sarcoma mimicking intraneural ganglion cysts and a literature review.

PRESENTATION OF CASE

We describe a 36-year-old female who presented to our clinic complaining of left leg pain for six years. MRI was done, which revealed a cystic lesion. With an impression of intraneural ganglion cyst versus nerve sheath tumor of the common peroneal nerve. The patient underwent exploration surgery and mass excision. The mass was sent for histopathology following excision, where the results indicated monophasic synovial sarcoma. An additional surgery, an epineurectomy of the common peroneal nerve and tumor bed excision, was followed by adjuvant chemotherapy with a Doxorubicin-based regimen. Following surgery, our patient's neurological symptoms improved.

CLINICAL DISCUSSION

The mainstay of treatment in synovial sarcoma is surgical excision with a Doxorubicin-based regimen of chemotherapy and/or radiotherapy based on tumor characteristics. Tumors smaller than 5 cm in MRI usually show homogenous enhancement and can be mistaken for benign tumors. Hence, a biopsy should be done before surgery to avoid misdiagnosis.

CONCLUSION

Even though it is extremely rare, synovial sarcoma of the lower extremity should be considered when a painful swelling of the lower leg is associated with a long duration of symptoms. Such lesions are best managed by surgical excision and postoperative chemotherapy.

Case report: skeletal muscle metastasis from follicular thyroid carcinoma presenting as synovial sarcoma

Differentiated thyroid carcinomas tend to remain localized and usually are of slow progression with excellent long-term survival. The major sites of distant metastases are cervical lymph nodes, lungs and bones and the minor sites include the brain, liver, pericardium, skin, kidney, pleura and muscle. Skeletal muscle metastases from differentiated thyroid carcinoma, are exceedingly rare. In this report, a 42-year-old woman with follicular thyroid cancer that had had a total thyroidectomy and radioiodine ablation nine years ago was presented with a painful right thigh mass and negative PET/CT scan. The patient had also lung metastases during the follow-up period which were treated with surgery, chemotherapy and radiation therapy. An MRI scan of the right thigh showed a deep-seated lobulated mass with cystic regions, bleeding elements and strong heterogeneous post contrast administration enhancement. Due to the similarities in clinical manifestations and imaging features between soft tissue tumors and skeletal muscle metastases, the case was initially misdiagnosed in favor of synovial sarcoma. Histopathological, immunohistochemistry and molecular analysis of the soft tissue mass confirmed to be a thyroid metastasis and, as a result, a final diagnosis of skeletal muscle metastasis was provided. Even though the probability of a skeletal muscle metastasis from thyroid cancer approaches zero, this study aims to raise the awareness to the medical community that these events do in fact occur in the clinical setting and should be considered in the differential diagnosis of patients with thyroid carcinomas.

A Large Primary Retroperitoneal Synovial Sarcoma: A Case Report of a Huge Malignant Tumor

Synovial Sarcoma (SS) is a rare soft-tissue malignancy. Only about 15% of SS originates from the retroperitoneum. Retroperitoneal SS (RSS) is usually diagnosed incidentally due to the anatomy of the retroperitoneum. The most common complaints of patients are abdominal and low back pain. Other common symptoms of RSS are palpable abdominal mass, weight loss, and anemia. In this study, we will describe a 29-year-old white Asian man with a diagnosis of RSS after radical nephrectomy. He was admitted to the Urology Department of Shohada-e Tajrish hospital, Tehran, Iran in March 2019. The distinguishing feature of this case is the size of the mass, which has never been reported so much for retroperitoneal synovial sarcoma. Radiologic imaging showed a huge retroperitoneal mass originating from the kidney. Based on the pathologic features and immunohistochemistry (IHC) study, the diagnosis was consistent with synovial sarcoma. Accurate diagnosis of RSS is usually based on the pathological findings. Therefore, in case of doubt, a biopsy can be employed. Surgical resection of the tumor and lymph nodes dissection is the main and most important part of the treatment. Aggressive resection with free margin is recommended. The role of adjuvant and neoadjuvant chemotherapy in RSS is not certain to date, but it is recommended according to the patient's condition.

A rare case of synovial sarcoma of diaphragm

Background

Primary diaphragmatic synovial sarcoma is a rare clinical entity with only few cases reported in the literature. It is found mainly in young adults, in the limbs. However, the name is a misnomer as it probably arises from primitive mesenchyme rather than articular surfaces of the joints.

Case

We report a case of 21‐year‐old patient with synovial sarcoma of the diaphragm, treated by complete surgical excision of the tumor with diaphragmatic reconstruction and confirmed on immunohistopathology. The peculiarity of this case stems from the atypical location of the tumor with complete surgical resection and thereby providing a better quality of life for the patient.

Conclusion

Synovial sarcoma of the diaphragm is a rare malignancy and more data and research is needed for defining the best management for this tumor.

Magnetic resonance imaging findings of synovial sarcoma in children: location-dependent differences

BACKGROUND

While overall survival for children is greater than that for adults, synovial sarcoma remains an aggressive neoplasm with a potentially poor prognosis, and its magnetic resonance imaging (MRI) findings in children are not well described.

OBJECTIVE

We aimed to characterize the spectrum of MRI findings of synovial sarcoma in children with respect to anatomical location and outcome.

MATERIALS AND METHODS

Children with histologically confirmed synovial sarcoma and preoperative MRI performed within the past 11 years (2009-2020) were included. Two radiologists retrospectively reviewed each MRI to categorize location, signal characteristics and associated findings. Chi-square and Fisher exact tests were used to assess associations with locations and outcomes.

RESULTS

This study included 23 children (13 girls, 10 boys; mean age: 12.7±4.2 years) with 7 axial, 8 proximal and 8 distal appendicular lesions. Kappa ranged from 0.53 to 1. MRI findings differed significantly between locations with axial lesions measuring larger (P=0.01) and more likely to contain fluid levels (P=0.02), triple sign (P=0.02), inhomogeneous signal (T1-weighted images, P=0.003; T2-weighted images, P=0.02, contrast-enhanced images, P=0.03) with all lesions containing partially solid composition (P=0.03). At a median follow-up of 14 months (interquartile range: 7-33 months), 39% relapsed. Predictors of relapse (P<0.05) included metastasis at presentation, larger lesions, axial lesions and MRI findings of fluid level, T1-weighted hyperintensity, inhomogeneous signal (T1- and T2-weighted images) and poorly circumscribed margins.

CONCLUSION

A significant association was found between location and MRI findings in our cohort of children with synovial sarcoma. Axial lesions were more likely to be larger, appear heterogeneous and be associated with a worse outcome.

Synovial sarcoma of the spinal canal and paraspinal muscle and retroperitoneum: a case with extensive calcification

INTRODUCTION

Synovial sarcoma (SS) is a rare mesenchymal malignant tumor. SS of the spine or retroperitoneum is an extremely rare site. Approximately 30% cases show focal calcifications on radiographs and computed tomography (CT) images, while extensive calcification rarely occurs. We presented a case of SS involving the spinal canal and paraspinal muscle and retroperitoneum, which showed extensive calcification on CT.

CLINICAL PRESENTATION

The present report describes the case of a 13-year-old girl suffering from a tumor in the spinal canal and paraspinal muscle and retroperitoneum with extensive calcification on CT. The patient underwent lumbar and retroperitoneal giant tumor resection, lumbar decompression, and spinal tumor resection with a small tumor remnant remaining in the paravertebral region. Histological examination and genetic testing after surgery confirmed synovial sarcoma. After surgery, the patient refused local radiotherapy but agreed to receive chemotherapy. After 4 months of follow-up, her condition was basically stable, and the pain in her left lower limb disappeared. The residual tumor was not increased.

CONCLUSION

Extensive calcification of SS is rare. The possibility of synovial sarcoma should be considered in those who show extensive calcification in the spinal canal and paraspinal muscle and retroperitoneum on CT. For cases that cannot be completely resected, adjuvant chemotherapy can control the residual tumor in the short term. In addition, the long-term effects need to be observed.

Magnetic resonance imaging of soft tissue sarcoma: features related to prognosis

Magnetic Resonance Imaging is a fundamental tool in the evaluation of soft tissue sarcoma. Imaging features are relevant for the assessment of treatment strategies, surgical planning and also for patients' prognosis prediction. Among soft tissue sarcoma and also other malignancies, the size of the mass is usually considered the prognostic key element in diagnostic imaging. Moreover, several other features should be obtained from MRI studies with prognostic implications in all type of soft tissue sarcoma: peritumoral enhancement, signs of necrosis, deep location, ill-defined borders/signs of infiltrations. Focusing on soft tissue sarcoma subtypes, some other magnetic resonance imaging features are more specific and related to prognosis. In myxofibrosarcoma the magnetic resonance imaging "tail sign" and a "water-like" appearance on fluid-sensitive sequences, due to rich myxoid matrix content, are both associated with higher risk of local recurrence after surgical excision; nevertheless, the "tail sign" is also related to a higher risk of distant metastases at diagnosis. The "tail sign" is associated with higher risk of local recurrence after surgical excision in undifferentiated pleomorphic sarcoma as well. In patients affected by synovial sarcoma, the "triple sign" identifiable in magnetic resonance imaging (T2w sequences) is associated with decreased disease-free survival and indicates the simultaneous presence of solid cellular elements (intermediate signal intensity), hemorrhage or necrosis (high signal intensity) and fibrotic regions (low signal intensity). In addition, absence of calcifications are associated with reduced disease-free survival in patients affected by synovial sarcoma. Signal heterogeneity is associated with worst prognosis in all type of soft tissue sarcoma, particularly in myxoid liposarcoma. In recent years, several new quantitative tools applied on magnetic resonance imaging have been proved to predict patients' prognosis. Above all the new tools, radiomics seems to be one of the most promising, and, has been proved to have the capability in discriminating low-grade from high-grade soft tissue sarcomas. Therefore, magnetic resonance imaging studies in patients with soft tissue sarcoma should be accurately evaluated and their results should be taken into account for prognostic assessment.

Synovial Sarcoma: A Clinical Review

Synovial sarcomas (SS) represent a unique subset of soft tissue sarcomas (STS) and account for 5–10% of all STS. Synovial sarcoma differs from other STS by the relatively young age at diagnosis and clinical presentation. Synovial sarcomas have unique genomic characteristics and are driven by a pathognomonic t(X;18) chromosomal translocation and subsequent formation of the SS18:SSX fusion oncogenes. Similar to other STS, diagnosis can be obtained from a combination of history, physical examination, magnetic resonance imaging, biopsy and subsequent pathology, immunohistochemistry and molecular analysis. Increasing size, age and tumor grade have been demonstrated to be negative predictive factors for both local disease recurrence and metastasis. Wide surgical excision remains the standard of care for definitive treatment with adjuvant radiation utilized for larger and deeper lesions. There remains controversy surrounding the role of chemotherapy in the treatment of SS and there appears to be survival benefit in certain populations. As the understanding of the molecular and immunologic characteristics of SS evolve, several potential systematic therapies have been proposed.

Configuration of soft-tissue sarcoma on MRI correlates with grade of malignancy

BACKGROUND

The aim of the study was to assess whether the configuration of primary soft-tissue sarcoma (STS) on MRI correlates with the grade of malignancy.

PATIENTS AND METHODS

71 patients with histologically proven STS were included. Primary STS were examined for configuration, borders, and volume on MRI. The tumors were divided into high-grade (G3), intermediate-grade (G2) and low-grade (G1) STS according to the grading system of the French Federation of Cancer Centers Sarcoma Group (FNCLCC).

RESULTS

30 high-grade, 22 intermediate-grade and 19 low-grade primary STS lesions were identified. High- and intermediate-grade (G3/2) STS significantly most often appeared as polycyclic/multilobulated tumors (p < 0.001 and p = 0.002, respectively). Low-grade (G1) STS mainly showed an ovoid/nodular or streaky configuration (p = 0.008), and well-defined borders. The appearance of high-, intermediate- and low-grade STS with an ovoid/nodular configuration were mainly the same on MRI. All streaky G3/2 sarcoma and 17 of 20 patients with polycyclic/multilobulated G3 sarcoma showed infiltrative borders. High-grade streaky and polycyclic/multilobulated STS are larger in volume, compared to intermediate- and low-grade STS.

CONCLUSIONS

Configuration of STS on MRI can indicate the grade of malignancy. Higher-grade (G2/3) STS most often show a polycyclic/multilobulated configuration, while low-grade STS are mainly ovoid/nodular or streaky. Infiltrative behavior might suggest higher-grade STS in streaky and polycyclic/multilobulated STS.

Diagnosis and management of primary malignant tumors in the upper extremity

Bone and soft tissue sarcomas of the upper extremity are relatively uncommon. In many cases, they are discovered incidentally during evaluation of traumatic injuries or common ailments such as rotator cuff tendonitis or tennis elbow. Thus, it is important for all orthopedic surgeons to understand the differential diagnosis, workup, and treatment for upper extremity lesions. An appreciation of the clinical and radiographic features of primary malignant lesions aids in identifying patients that need referral to an orthopedic oncologist and a multidisciplinary team.

Sinonasal synovial sarcoma: evaluation of the role of radiological and clinicopathological features in diagnosis

AIM

To explore the value of radiological and clinicopathological features in the diagnosis of sinonasal synovial sarcomas (SS).

MATERIALS AND METHODS

Six patients with sinonasal SS were studied retrospectively using computed tomography (CT; n=6) and magnetic resonance imaging (MRI; n=4). The radiological and clinicopathological findings in this series were reviewed.

RESULTS

Three lesions were located, in both the nasal cavity, and the paranasal sinuses; one was located in the nasal cavity and nasopharynx, and the remaining two were located restrictively within the nasal cavity. An aggressive nature (invasion of adjacent structure) was found in four cases. At CT, lesions were found with isodensity with calcification mainly in the peripheral areas. Bony changes were visible in all cases. Five cases showed marked heterogeneous enhancement, and three cases contained necrotic or cystic areas. At MRI, haemorrhage was observed in three cases. All cases demonstrated the "triple sign", and two high-grade SS showed a "cobblestone-like" appearance on T2-weighted imaging (WI). All time-signal intensity curves (TICs) were of the washout type. The mean apparent diffusion coefficient (ADC) values of the two high-grade cases were lower than those of the low-grade or intermediate-grade cases. Histopathologically, all but one was of the monophasic type. During the 8-40 month period of follow-up, recurrence occurred in four cases.

CONCLUSIONS

A sinonasal tumour exhibiting characteristic calcification and bony change, together with haemorrhage, "triple sign" or "cobblestone-like" appearance, should engender a diagnosis of SS.

Overview of the clinical and imaging features of the most common non-rhabdomyosarcoma soft-tissue sarcomas

Non-rhabdomyosarcoma soft-tissue sarcoma (NRSTS) refers to a widely heterogeneous group of extraskeletal mesenchymal neoplasms accounting for approximately 4% of all childhood cancers. This article summarizes the clinical and imaging features of these rare tumors and describes in detail the three most common histological types of NRSTSs encountered in children - synovial sarcoma, malignant peripheral nerve sheath tumor and infantile fibrosarcoma. The author discusses the role of non-cross-sectional and cross-sectional imaging.

Synovial sarcoma in the plantar region: A case report and literature review

BACKGROUND

Synovial sarcoma (SS), a rare malignant soft tissue tumor whose histological origin is still unknown, often occurs in limbs in young people and is easily misdiagnosed.

CASE SUMMARY

We report a 24-year-old man who sought treatment for plantar pain thought to be caused by a foot injury that occurred 4 years prior. Currently, he had been seen at another hospital for a 1-wk history of unexplained pain in the left plantar region and was treated with acupuncture, a kind of therapy of Chinese medicine, which partly relieved the pain. Because of this, the final diagnosis of biphasic SS was made after two subsequent treatments by pathological evaluation after the last operation. SS is rarely seen in the plantar area, and his history of a left plantar injury confused the original diagnosis.

CONCLUSION

This study shows that pathological and imaging examinations may play a vital role in the early diagnosis and treatment of SS.

Gouty Tophi in Sinus Tarsi of Bilateral Feet Mimicking Synovial Sarcoma:A Case Report

Chronic gout is defined as accumulation of monosodium urate crystals in joints, cartilage, tendons, bursae, bone, and soft tissue. The foot is the most common location for acute gout flares, with the first metatarsophalangeal joint being the most frequent site of tophus formation. However, few studies have reported gouty tophus formation in the subtalar joint. Gout has been termed the "great mimicker" because of its tendency to mimic other pathologic conditions, such as pigmented villonodular synovitis and synovial sarcoma. Herein, we present a rare case of chronic tophaceous gout in the sinus tarsi in both feet in a 23-year-old healthy male, with extensive bony erosions mimicking pigmented villonodular synovitis and synovial sarcoma. We discuss the clinical presentation, distinguishing radiologic characteristics, surgical procedures, and outcome regarding this unique presentation.

Imaging of rare appendicular non-acral soft-tissue chondromas in adults with histopathologic correlation

Background Soft-tissue chondroma (STC) is a rare benign soft tissue tumor that arises primarily in acral extra-skeletal locations. Occasionally, STCs may arise in more proximal non-acral locations, accompanied by non-classic features that label them as indeterminate lesions and pose diagnostic challenge for both radiologists and pathologists alike. Purpose To explicate the potential of diagnostic imaging in the identification and characterization of appendicular non-acral STCs with emphasis on their morphologic magnetic resonance imaging (MRI) enhancement. Material and Methods Our clinical database records were searched for patients with histologically proven primary soft-tissue chondroid lesions over a five-year period. Two musculoskeletal (MSK) trained radiologists evaluated the imaging studies and an MSK pathologist revised the pathological findings. Results The study included six cases of appendicular non-acral STCs (mean age = 40.5 years). The mean size of the tumors was 5.6 cm, with four localized to the knee region, one in the thigh, and one in the sternoclavicular region. All cases showed high signal intensity matrix with low-signal intensity septa on T2-weighted MRI and post-contrast marginal/septal enhancement. The lesions were lobulated and lacked host tissue reaction except for one showing subjacent mild soft-tissue edema. Histologically, the cases lacked overt features of malignancy although one was originally misdiagnosed as chondrosarcoma. Conclusion Non-acral STCs are benign cartilaginous tumors that may pose a diagnostic challenge, both radiologically and pathologically. Collaborative imaging and pathologic workup is needed for better characterization of non-aggression of these lesions, and to avoid diagnostic pitfalls and unnecessary radical resections.

Omental synovial sarcoma mimicking an ovarian malignancy: A case report

Synovial sarcoma is clinically rare, and cases of synovial sarcoma arising in the omentum are particularly rare. Only 3 cases have been reported in the literature to dtae, and they were associated with a poor prognosis. We herein report a rare case of aggressive primary omental synovial sarcoma presenting as an ovarian malignancy. A 53-year-old multigravida woman was referred to our hospital due to progressive abdominal distension. Magnetic resonance imaging revealed a large heterogeneous mass with an irregular component occupying the lower abdominal cavity, with an intact uterus. Intraoperative examination revealed a solid mass arising from the lower omentum. The diagnosis of omental synovial sarcoma was established based on postoperative pathological and immunohistochemical examination of the tumor. The patient underwent multiple surgical resection procedures due to the development of metastases in the liver, lungs and abdominal cavity and received adjuvant chemotherapy including doxorubicin-ifosfamide, pazopanib and trabectedin. Such rare neoplasms may be difficult to diagnose preoperatively based on radiological examinations alone. Thus, gynecologists should be aware of the possibility of omental synovial sarcoma, and combined surgical and chemotherapeutic interventions are required to control such aggressive tumors.

Monophasic Synovial Sarcoma of Prostatic Fascia: Case Report and Literature Review

Synovial sarcoma (SS) primarily occurs in the para-articular soft tissue of the lower extremities in young adults and it is extremely rare in the prostatic region. We report a case of a 46-year-old man who presented with urinary retention. Pelvic ultrasound (US) examination, computed tomography (CT), and magnetic resonance imaging (MRI) demonstrated an 8.5 cm mass that appeared to originate in the prostatic fascia of the right lobe. Preoperative prostatic ultrasound transrectal needle biopsy revealed mesenchymal neoplastic tissue. Patient underwent surgery. The final pathologic findings were consistent with the diagnosis of monophasic synovial sarcoma.