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.

[Imaging characteristics and diagnosis of primary middle mediastinal tumors].

Objectives: To investigate the proportion of different histological types and CT enhanced imaging features of primary middle mediastinal lesions in order to improve the understanding of these tumors and the accuracy of preoperative diagnosis. Methods: Retrospective analysis was conducted on 84 patients with primary middle mediastinal lesions and clear histological classifications diagnosed and treated at the Cancer Hospital, Chinese Academy of Medical Sciences from January 2012 to December 2022. Clinical, imaging, and pathological data were collected and classified according to tumor histological classifications. CT imaging manifestations such as tumor location, size, morphology, edge, boundary, internal components, enhancement characteristics, and surrounding tissue invasion were evaluated and recorded. Results: The histological types of the primary middle mediastinal lesions from the 84 patients included mesenchymal tumors, anterior intestinal cysts, giant lymph node hyperplasia, substernal goiter, neuroendocrine carcinoma, lymphohematopoietic system tumors, and mesothelioma, accounting for 28.6%, 27.4%, 14.3%, 3.6%, 11.9%, 9.5%, and 4.8%, respectively. Mesenchymal tumors included peripheral nerve sheath tumors, vascular tumors, adipogenic tumors, solitary fibrous tumors, and synovial sarcoma, accounting for 54.2%, 20.8%, 12.5%, 8.3%, and 4.2%, respectively. The above tumors had diverse imaging manifestations and specific imaging features. Mature fat were found in 3 cases of liposarcoma; Calcification was observed in 2 cases of thyroid nodules and 7 cases of giant lymph node hyperplasia; Enhanced scanning showed significant enhancement in 2 cases of solitary fibrous tumors, 3 cases of thyroid nodules, and 11 cases of giant lymph node hyperplasia; Mediastinal large lymph nodes was observed in 6 cases of lymphoma and 3 cases of mesothelioma; High invasiveness was observed in 4 cases of mesothelioma and 9 cases of neuroendocrine carcinoma. Conclusion: Mediastinal tumors have low incidence rate and rich histological types, and their imaging manifestations are diverse. Preoperative differential diagnosis can be made according to their specific imaging characteristics.

[Repeated Pericardial Effusion Leading to the Diagnosis of Synovial Sarcoma:Report of a Case].

The patient is a 76-year-old man. His chief complaint of chest pain led to a diagnosis of pericardial effusion of unknown cause, and pericardial drainage was performed. On the 30th day, chest pain appeared again. Echocardiography revealed a pericardial fluid reaccumulation and a substantial mass in the pericardial space. Surgical drainage was performed to find the cause. A hematoma/mass was present on the epicardium. The pericardial sac was filled with hematoma. The hematoma was removed, but part of the mass infiltrated close to the anterior descending branch of the left coronary artery, and removal of that part was abandoned. The intrapericardial hematoma and epicardium were submitted to pathology leading to the diagnosis of synovial sarcoma. The patient was discharged home 14 days after surgery.

Prognostic factors of the synovial sarcoma of the extremities: imaging does matter.

OBJECTIVES: Synovial sarcomas (SS) of the extremities are rare soft tissue sarcomas that are more common in young adults. We deciphered the imaging phenotype of SS with the aim to determine if imaging could provide an incremental value to currently known prognostic factors (PF)-age and histological grade-to predict long-term overall survival (OS). METHODS: This retrospective multicenter study included consecutive pediatric and adult patients with synovial sarcomas of the extremities from December 2002 to August 2020. Inclusion criteria were (i) a follow-up greater than 5 years and (ii) available pre-therapeutic MRI. A subset analysis included MRI and CT-scan. Clinical, pathological, and imaging variables were collected in all patients. The primary endpoint was to evaluate the association of these variables with OS using univariate and multivariate Cox regressions. RESULTS: Out of 428 patients screened for eligibility, 98 patients (mean age: 37.1 ± 15.2 years) were included (MRI: n = 98/98, CT scan: n = 34/98; 35%). The median OS was 75.25 months (IQR = 55.50-109.12) and thirty-six patients (n = 36/98;37%) died during follow-up. The recurrence rate was 12.2% (n =12/98). SS lesions were mostly grade 2 (57/98; 58%). On MRI, SS had a mean long-axis diameter of 67.5 ± 38.3 mm. On CT scan, 44% (15/34) were calcified. Grade (hazard ratio [HR] = 2.71; 95%CI = 1.30-5.66; p = 0.008), size of the lesions evaluated on MRI (HR = 1.02; 95% CI = 1.01-1.03; p < 0.001), and calcifications on CT scan (HR = 0.10; 95% CI = 0.02-0.50; p = 0.005) were independent PF of OS. CONCLUSIONS: This study demonstrated that imaging biomarkers can be used to predict long-term outcome in patients with SS. Strikingly, the presence of calcifications on CT scan is associated with favorable outcome and provides an incremental value over existing PF such as age, grade, and size. KEY POINTS: • Beyond its diagnostic value, MRI is a pre-operative prognostic tool in synovial sarcomas of the extremities since the size of the lesion is an important prognostic factor. • Calcifications on CT scans are independently and significantly associated with prolonged overall survival.

Synovial sarcoma of the tibial nerve - case report of a rare tumor in a rare location requiring early diagnosis.

BACKGROUND: We present the case of a patient with a rare synovial sarcoma (SS) of the tibial nerve. So far, only 4 cases of patients with SS originating from the tibial nerve have been described in the literature, and our patient is only the second patient whose limb was saved during treatment. Synovial sarcomas are malignant mesenchymal tumors, i.e., tumors arising from connective tissue. Synovial sarcomas account for 5-10% of all soft tissue sarcomas. However, the name synovial sarcoma is misleading, because the tumor does not originate from synovial cells, but rather from primitive mesenchymal cells. The name most likely originated from the localization around the large joints on the limbs, more often on the lower ones, in the area of the knee joints. We point out the aspects of correct and quick diagnosis and subsequent treatment, which has very important effect on the patient's prognosis. Primary less radical excision without prior biopsy verification leads to a higher risk of local recurrence, even if a proper reexcision was performed immediately after biopsy verification of the sarcoma. CASE PRESENTATION: A woman born in 1949 began to suffer at the end of 2020 with escalating pain under the left inner ankle with a projection to the sole and fingers. Her personal, family work and social history were insignificant. After the initial neurological examination, the patient was sent for an ultrasound examination of the ankle, which showed a lobular mass measuring 50 × 22 × 16 mm and according magnetic resonance imaging, the finding appeared to be a suspicious neurinoma of the tibial nerve. The tumor was surgically excised, without prior biopsy verification: a 50 × 20 mm tumor was dissected in the distal part of the tarsal canal, which grew through the structure of the tibial nerve and in some places into the surrounding area and appeared intraoperatively as a neurofibroma. But histologically the tumor was classified as monophasic synovial sarcoma. The patient was indicated for a wide reexcision of the skin with the subcutaneous tissue of size 91 × 20 × 15 mm. Now the patient is being treated with external radiotherapy to the tumor bed and she is able to walk. CONCLUSION: This report draws attention to a rare type of malignant nerve tumor, which both clinically and radiologically can mimic benign peripheral nerve sheath tumors. Synovial sarcoma should be considered in very painful resistances, typically located around the joints of the lower limbs, the growth of which can be slow. Because the size of the tumor is a negative prognostic factor, it is necessary to make a timely diagnosis using MR imaging and a biopsy with histological examination and to start treatment quickly. Surgical treatment should take place only after a biopsy with histological examination of the tumor so that it is sufficiently radical and does not have to undergo an additional reoperation, as happened in the case of our patient.

Synovial sarcoma: a rare neoplasm of paranasal sinus.

Synovial Sarcoma (SS) is a rare soft-tissue malignant tumour. Its presentation in the head and neck region is uncommon. Because of the complex anatomy of the head and neck region, surgery with clear margins is not achievable. In such cases, a multi-modality approach is required as there is no established standard of care. In this report, we share the case of a girl who presented with nasal obstruction. Imaging revealed a mass involving the left nasal cavity, paranasal sinuses without intracranial extension. It was diagnosed as synovial sarcoma. She underwent surgical excision and adjuvant radiation therapy (RT) to the tumour bed, followed by an incomplete course of chemotherapy. Later on, she developed systemic disease. Considering the rarity of this case and lack of guidelines for standard treatment, we report on this case to share our experience with management and treatment outcome.

Primary Pleuropulmonary Synovial Sarcoma: Report of Two Cases and a Comprehensive Review of the Literature.

Primary sarcomas of the lung represent less than 0.5% of all primary lung tumors and comprise a heterogeneous group of malignancies including synovial sarcoma (SS). Primary pleuropulmonary SS has non-specific presentations, such as chest pain, shortness of breath and cough, and its associated imaging features resemble those of other intrathoracic malignancies. The diagnosis of these tumors needs to be confirmed by cytogenetic and molecular studies. Here, we describe two rare cases of primary pleuropulmonary SS who were admitted to our hospital. We also provide a concise review of clinical, radiological, and histopathological characteristics of pleuropulmonary SS after exploring 168 studies (415 corresponding patients) that were identified through a literature search.

Case 290: Intravascular Cystic Synovial Sarcoma.

History A 26-year-old man presented with a 1-month history of chest pain, a palpable and painful right inguinal mass, and edema in the right lower extremity. One month earlier, he started to experience left chest pain with no cough. Pulmonary CT angiography (CTA) revealed a left lower lobe segmental pulmonary embolus. The local hospital made a diagnosis of pulmonary embolism. He received anticoagulants, and his chest pain was gradually relieved. At the time of current presentation, the patient was experiencing right lower extremity swelling and pain. Physical examination revealed a 4 × 3 cm palpable right inguinal mass with no redness. His medical history and family history were negative. The results of laboratory work-up were normal, with a d-dimer level of 0.16 mg/L fibrinogen equivalent units (reference range, <0.46 mg/L) and an international normalized ratio of 2.45 (therapeutic range, 2.0-3.0 for a patient taking warfarin), except the prothrombin time was 28.2 seconds (reference range, 9.6-12.8 seconds) and the activated partial thromboplastin time was 52.2 seconds (reference range, 24.8-33.8 seconds). Echocardiography, chest radiography, chest CT, and contrast-enhanced (CE) CT revealed no abnormalities. The patient underwent right lower extremity vascular conventional US (Philips IU22; Philips) with an L9-3 probe (3-9 MHz, venous condition) and contrast-enhanced US (1.5-2.0 mL, SonoVue; Bracco) with an intravenous bolus injection at the initial evaluation. Two days later, noncontrast and contrast-enhanced CT images of the lower abdomen (1.5 mL per kilogram of body weight, 300 mg/mL iomeprol, Iomeron; Bracco) were acquired for further evaluation.

The Biology of Synovial Sarcoma: State-of-the-Art and Future Perspectives.

OPINION STATEMENT: New molecular insights are being achieved in synovial sarcoma (SS) that can provide new potential diagnostic and prognostic markers as well as therapeutic targets. In particular, the advancement of research on epigenomics and gene regulation is promising. The concrete hypothesis that the pathogenesis of SS might mainly depend on the disruption of the balance of the complex interaction between epigenomic regulatory complexes and the consequences on gene expression opens interesting new perspectives. The standard of care for primary SS is wide surgical resection combined with radiation in selected cases. The role of chemotherapy is still under refinement and can be considered in patients at high risk of metastasis or in those with advanced disease. Cytotoxic chemotherapy (anthracyclines, ifosfamide, trabectedin, and pazopanib) is the treatment of choice, despite several possible side effects. Many possible drug-able targets have been identified. However, the impact of these strategies in improving SS outcome is still limited, thus making current and future research strongly needed to improve the survival of patients with SS.

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.

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.

Laparoscopic intragastric resection of gastric synovial sarcoma: report of the first ever case with video demonstration.

BACKGROUND: Synovial sarcoma (SS) is a rare soft tissue tumor. Among different anatomical locations where it can be found, gastric localization is a very uncommon one. Based on soft tissue sarcoma guidelines, complete tumor excision is considered the main treatment approach. Depending on size and localization of the tumor, both wedge and major gastric resections have been performed in the past for the treatment of this condition. CASE PRESENTATION: We present the case of a 43-year-old woman who underwent a laparoscopic intragastric excision of a gastric 10-mm SS located nearby the esophagogastric junction. Pathology examination confirmed the presence of a SS. The resected specimen confirmed margin-free excision of a monophasic spindle cell neoplasm invading the submucosa and presenting the rearrangement of SS18 gene at fluorescence in situ hybridization (FISH). No adjuvant treatment was offered, and 18 months after surgery, the patient was alive and disease free. CONCLUSIONS: This represents the first case reported in literature of a laparoscopic intragastric resection for a gastric SS. This approach allowed to obtain a full thickness radical tumor resection with the advantages of minimally invasive and organ preserving surgery.

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.

The Imaging Spectrum of Synovial Sarcomas: A Pictorial Review From a Single-Centre Tertiary Referral Institution.

Synovial sarcomas are malignant soft-tissue tumors that typically affect young patients. They can arise from nearly anywhere in the body, most commonly the extremities, head and neck, and thorax. The imaging features are highly variable and depend on the anatomic origin. Most lesions present as large aggressive heterogeneous masses containing hemorrhagic and cystic foci, often with calcification. However, up to one-third of lesions have commonly benign features and can appear homogeneously solid or cystic. Especially in these cases, their innocuous imaging and clinical presentation can lead to delayed diagnosis. Therefore, knowledge of the imaging spectrum is crucial to ensuring adequate follow-up or timely pathologic sampling. We reviewed 30 pathologically proven cases in various anatomic sites from our institution to illustrate these characteristics.

Neck exploration for a huge synovial sarcoma, case report and literature review.

A 47-year-old woman presented in the outpatient department of EAST Surgical ward of MAYO Hospital Lahore, Pakistan, on February 2019 with complaint of swelling in the front section of the neck since five months which increased gradually in size and had been causing pain since two months. She had no comorbidities and insignificant family history. Examination revealed a 23×20 cm mass on the right side of the posterior triangle of the neck. Fine Needle Aspiration Cytology (FNAC) was inconclusive and CT of the neck showed a huge mass on the right side of the neck with cervical lymph nodes. Exploration was planned, and modified radical neck dissection Type III (Also known as Functional Neck dissection) was performed. The biopsy revealed synovial sarcoma of the neck. The patient's post-operative condition was satisfactory and she was discharged on the fifth post-operative day.

Anterior Abdominal Wall Synovial Sarcoma: A Rare Presentation.

Abdominal wall sarcoma belongs to a heterogeneous group of uncommon malignant neoplastic conditions with differentiated morphological patterns and originating from mesenchymal tissues. Soft tissue sarcomas predominantly involve the lower and upper limbs and retroperitoneum. We present a case of a 30-year-old patient, complaining of swelling in the left flank whose magnetic resonance imaging (MRI) revealed a solid tumour on the abdominal wall of the flank and biopsy turned out to be synovial sarcoma.

[Intra-abdominal recurrence with bleeding 7 years after curative resection of primary synovial sarcoma of the spermatic cord with localized dissemination:a case report].

Primary synovial sarcoma of the spermatic cord is quite rare and has not been reported in Japanese literature. We report a case of primary synovial sarcoma of the spermatic cord and localized dissemination of the tumor in a patient who experienced recurrence of intra-abdominal bleeding 7 years after curative resection of the primary lesion. A 70-year-old man was admitted with disturbance on urination and lower abdominal pain. Computed tomography (CT) of the abdomen revealed two lesions:a 10-cm intrapelvic tumor with hemorrhage and a 4-cm tumor adjacent to the bladder. Curative excision of the tumors was performed. Histological examination revealed that the larger lesion was a primary tumor of the spermatic cord with proliferation of spindle cells in cellular fascicles in a monotonous pattern, which was compatible with histologic findings of monophasic fibrous synovial sarcoma. The smaller lesion was a disseminated tumor. The diagnosis of synovial sarcoma was confirmed by the detection of a SS18 (SYT) -SSX1 fusion gene. After discharge, the patient received adjuvant chemotherapy, including ifosfamide and doxorubicin. No recurrence was evident thereafter. Seven years after the operation, the patient experienced sudden abdominal pain and swelling and was transferred to our hospital. CT showed a 17-cm tumor with massive hemorrhage in the omental bursa. Through catheterization of the superior mesenteric artery, bleeding from a branch of the dorsal pancreatic artery was identified. Because of the difficulty of catheterizing the bleeding branch, he underwent emergency resection of the tumor and partial resection of the colon. Histologic examination and genetic testing revealed that the tumor was a recurrence of the synovial sarcoma. After discharge, the patient received treatment with gemcitabine and docetaxel. However, 7 months after the second surgery, intraperitoneal manifestations recurred. The patient died 14 months after the second resection. This case suggests that curative surgical resection of the primary synovial sarcoma of the spermatic cord contributes to prolonged survival. However, because the recurrence rate of synovial sarcoma is high, multidisciplinary treatment, including chemotherapy and radiotherapy, might be necessary.

Synovial sarcoma mimicking a thoracic dumbell schwannoma- a case report.

Introduction: Synovial sarcoma is a rare mesenchymal malignant neoplasm that accounts for less than 10% of soft tissue sarcomas. About 95% of the sarcomas occur in the extremities. Primary synovial sarcomas of the spine are a rare tumor arising from the paravertebral regions, paraspinal muscles or epidural spaces.Purpose: To report an atypical radiological presentation of synovial sarcoma of the thoracic spine mimicking a nerve sheath tumor in an elderly adult and describe the management with review of the literature.Clinical presentation: A forty-six-year-old lady presented with clinical features of a thoracic intradural extramedullary cord compression at T7 level. She was Nurick grade 4 at presentation. MRI of the Thoracic spine with whole spine screening showed a contrast enhancing intradural extramedullary tumor at the T7-8 level; the tumor was exiting out through the left T7-8 neural foramina with foraminal widening. The possibility of a schwannoma was considered.Intervention: She underwent a T7-8 laminectomy and total excision of the tumor followed by posterior fusion. The biopsy was reported as synovial sarcoma. She subsequently underwent radiation and chemotherapy. She had marked improvement in her Neurological status and remained disease free at six months follow-up.Conclusion: Synovial sarcoma of the spine is a rare mesenchymal malignant neoplasm. One needs to consider Synovial sarcoma as one of the differential diagnosis of intradural tumors of the spine.

Unusual Mimicker of the Carotid Body Tumor: Synovial Sarcoma of the Carotid Space.

Synovial cell sarcomas are malignant tumors originating from pluripotent mesenchymal stem cells, unlike its name. It is a common tumor in the periarticular area, accounting for 8% of all soft tissue sarcomas. Head and neck are among the rarest areas of this tumor. Synovial sarcomas of the head and neck are more aggressive than those seen in other regions and are associated with remarkable mortality and morbidity. Treatment of synovial sarcomas of the head and neck is usually extensive local excision and additional radiation and/or chemotherapy may be performed.

Soft-Tissue Tumors of the Hand-Imaging Features.

Imaging studies of the hands and fingers are common, and radiologists are generally comfortable with traumatic and degenerative conditions which arise frequently in daily practice. However, a variety of common and uncommon soft-tissue tumors also occur in the hand, the appropriate diagnosis of which can be a source of confusion for both clinicians and radiologists. These lesions often have overlapping imaging characteristics; however, a structured approach can help provide a focused differential diagnosis and impact further workup and management. We discuss several such tumors, categorizing them as cystic-appearing, noncystic masses along tendons and aponeuroses, adipocytic tumors, vascular lesions, and miscellaneous lesions with imaging features that can aid diagnosis.