Synovial sarcoma of bone: Sarcoma typically of soft tissues presenting as a primary bone tumor

Synovial sarcoma: the misdiagnosed sarcoma

Synovial sarcoma is a rare and highly malignant soft tissue sarcoma. The inconspicuous and diversity of its early symptoms make it a highly misdiagnosed disease. The management of synovial sarcomas is challenging as they are rare and have a poor prognosis. Early and correct diagnosis and treatment are critical for clinical outcomes. Misdiagnosis or delayed diagnosis can have devastating consequences for the patient. The detection of SS18 gene rearrangement is considered a powerful tool in establishing the diagnosis of synovial sarcomas. Biopsies and testing for gene rearrangements are recommended for all patients in whom SS cannot be excluded. Surgery is the mainstay of treatment for synovial sarcomas. Neoadjuvant/adjuvant radiotherapy is recommended for patients with big tumors (>5 cm) or positive resection margins, and neoadjuvant/adjuvant chemotherapy is recommended for patients with high-risk tumors or advanced diseases. This article reviews synovial sarcomas from the perspectives of clinical and radiological presentation, histological and cytogenetic analysis, differential diagnosis, treatment, and prognosis.

Limb conservation surgery in biphasic synovial sarcoma of thigh with vascular involvement: A race against time

INTRODUCTION

Synovial sarcomas are malignant soft tissue neoplasm representing 5 to 10 % of all Soft tissue sarcoma with incidence of 2.75 per 100,000. It is presented in particular along with extra articular location with no as such relation to synovial structures. Among various histological pattern biphasic synovial sarcoma (SS) is considered classical type. Involvement of neurovascular structures in synovial sarcoma is least noted and such invasion by malignant cells is considered an indication for amputation. However vessel reconstructive surgeries have also resulted in conservation of limb hence providing good quality of life.

CASE PRESENTATION

13 years old Asian female presented with complaint of exposed synthetic vessel graft from her previous surgical site where femoral vessel reconstruction was carried out for SS of thigh with femoral vessel involvement. Following her (wide local excision) WLE and femoral vessel reconstruction in another center she suffered thrombosis of her femoral vessel following which emergency thrombectomy was also carried out. Later in our center vertical rectus abdominis myocutaneous flap (VRAM) flap was used to manage her exposed synthetic graft. At subsequent follow up patient was ambulating well with no signs of radiological metastasis.

CLINICAL DISCUSSION

Surgical resections of mass along with synthetic graft placement of the concomitant vascular bundle have also shown significant improvement in reducing the burden of the severe diseases such as synovial sarcoma.

CONCLUSION

SS with its malignant pathophysiology have impacted severely the quality of life of even among the pediatrics group of population. It is utmost need to set up proper and definitive muscular oncological care to reduce the morbidity and mortality associated with such malignancies.

Intraosseous synovial sarcoma of the mandible: A case report and review of the literature

Synovial sarcoma (SS) is a malignant soft tissue tumor that usually arises in the para-articular regions of the extremities. Only nine cases of SS in the mandible have been reported to date. The present study described a case of SS arising from the left mandible. A 54-year-old woman was referred to Kyushu University Hospital (Fukuoka, Japan) with a complaint of numbness in the left mental nerve area. Computed tomography revealed replacement of the left mandibular bone marrow with soft tissue and destruction of the mandibular canal. Magnetic resonance imaging revealed an isointense mass on T1-weighted images and hyperintensity on T2-weighted images. The tumor showed homogeneous enhancement. A biopsy was performed, and monophasic SS was diagnosed based on immunohistochemical staining features and genetic analysis. Hemimandible dissection and supraomophyoid neck resection were performed with fibular osteocutaneous flap reconstruction, followed by adjuvant chemotherapy. There was no evidence of recurrence or distant metastases. The present study also reviewed the clinical, imaging, histological, and immunohistochemical features of the SS in the mandible.

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.

A rare incidence of primary Synovial Spindle Cell Sarcoma in a 46-year-old male, successfully managed by surgical intervention-A Case Report

INTRODUCTION AND IMPORTANCE

Synovial sarcoma (SS) is a rare form of Soft Tissue Sarcoma (STS) which results from the malignant proliferation of mesenchymal cells. Specific etiologies are not yet known, and its incidence rate ranges between 0.81 and 1.42 per 1 million individuals. Its gender-specific prevalence is almost the same between males and females and it is unique from other subtypes of STS in that it's slow growing and in almost half the cases, patients present with distant metastasis at the time of diagnosis.

CASE PRESENTATION

We present the case of a 46-year-old previously healthy male patient, who complained from a right lower extremity painless bulge, which began to be visibly noticeable by the patient 2 months prior to admission. There were no signs of allocated inflammation nor lower limb ischemia. Radiology revealed an irregular mass formation conformant with neoplasia.

CLINICAL DISCUSSION

Surgical resection of the mass along with synthetic graft replacement of the concomitant vascular bundle. Histopathological analysis of the resected mass revealed a monophasic synovial spindle cell sarcoma.

CONCLUSION

SS is a rare neoplasm poses a grave risk for patients due to its malignant pathophysiology and the wide margin of misdiagnoses. It is pivotal to set-up proper preoperative diagnostic guidelines for it and maintain high clinical suspicion so that we can bring down the high rates of the morbidity and mortality which ensue from this malignancy.

Case Report: Primary Intraosseous Poorly Differentiated Synovial Sarcoma of the Femur

Primary intraosseous poorly differentiated synovial sarcoma is exceedingly rare. Here, we present a case of primary intraosseous poorly differentiated synovial sarcoma from the proximal femur in a 16-year-old girl. The case was initially misdiagnosed, but the correct diagnosis of synovial sarcoma was eventually confirmed by fluorescence in situ hybridization and next-generation sequencing. We review the literature pertaining to synovial sarcoma and show that this case is the second molecularly proven intraosseous poorly differentiated synovial sarcoma in the literature. Recognition of intraosseous synovial sarcoma composed of small round cells is imperative in order to avoid misdiagnosis of the tumor as Ewing sarcoma and other small round-cell tumors, all of which have markedly different clinical management.

Sarcoma sinovial insidioso de osso em um paciente com artrite reumatoide

Sarcoma sinovial é uma rara malignidade de origem mesenquimal; a abordagem diagnóstica geralmente começa documentando um tumor de tecido mole; no entanto, resulta em um diagnóstico desafiador quando é mais profundo, de pequeno porte ou primário do osso.

O presente relato descreve um paciente que apresentou dor insidiosa no quadril atribuída a artrite reumatoide, com desfecho fatal devido a doenças de base e complicações cirúrgicas.

A subestimação da dor no quadril, principalmente quando não há massa palpável, pode atrasar o diagnóstico.

Knowledge of cytogenetic analysis for synovial sarcoma in sarcomatoid variant renal cell carcinoma

Sarcomatoid change in a renal tumor should undergo cytogenetic analysis of t(x;18) to prevent a missed diagnosis of synovial sarcoma. Surgeons should be vigilant regarding pathological correlation.

The rare primary bone sarcomas: imaging-pathological correlation

Rare primary bone sarcomas are challenging entities both radiologically and pathologically. These include the diagnoses of spindle cell sarcoma (leiomyosarcoma, fibrosarcoma, synovial sarcoma, and malignant peripheral nerve sheath tumor), pleomorphic liposarcoma, and undifferentiated pleomorphic sarcoma. The radiographic and cross-sectional imaging features of each of these tumors are presented, along with current key pathological concepts. Frequently non-specific, the radiological appearances must be correlated with all clinical and pathological information available to enable an accurate diagnosis.

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.

Feasibility of MRI in diagnosis and characterization of intra-articular synovial masses and mass-like lesions

Background

Classifications of intra-articular masses are infectious granulomatous diseases, non-infectious synovial proliferative processes (synovial chondromatosis, lipoma arborescens, rheumatoid arthritis, pigmented villonodular synovitis [PVNS]), vascular malformations, deposition disorders, neoplastic, and miscellaneous conditions. The aim of this study is to correlate the results of MRI with arthroscopy in characterization of different varieties of intra-articular synovial masses and mass-like lesions. This observational prospective study was conducted between February 2018 and August 2019. We screened 1000 routine musculoskeletal MRI examination during this period, 32 of which showed intra-articular synovial masses/mass-like lesions. The selected 32 patients (20 males and 12 females) have a mean age of 49.20 ± 2.0 years; all presented with joint swelling, pain, or difficulty of movement according to the joint affected. All patients underwent arthroscopy for histopathological correlation.

Results

The final diagnosis was synovial chondromatosis in 14 patients (43.8%), PVNS in ten patients (31.3%), and lipoma arborescens in five patients (15.6%). Synovial chondrosarcoma, synovial hematoma, and synovial ganglion cyst each in one patient (3.1%). The concordance of MRI to arthroscopy was 96.6% accuracy, 91.7% sensitivity, 99% specificity, 52.3% PPV, and 99.9% NPV.

Conclusion

Good correlation was observed between MRI and arthroscopy in diagnosis of intra-articular synovial masses/mass-like lesions.

Primary Intraosseous Synovial Sarcoma with Molecular Confirmation: Expanding and Clarifying the Spectrum of This Rare Neoplasm

Synovial sarcoma is a well-known malignant tumor usually originating within deep soft tissues of the lower extremities of adolescents and young adults. Rare radiologically confirmed examples of primary bone synovial sarcoma have been documented, generally in isolated case reports. Herein, we report two cases of primary intraosseous synovial sarcoma, with molecular confirmation, involving the left humerus of a 45-year-old female and the right fourth metatarsal bone in a 36-year-old male. Additionally, we clarify the spectrum of primary intraosseous synovial sarcoma by separately analyzing reported cases with radiographic confirmation of bone origin and molecular support for the diagnosis. There are clinicopathologic differences between those tumors with documented molecular confirmation and those lacking such confirmation, specifically regarding their anatomic distribution (p < 0.0001). Regarding the radiology of our two cases, the humeral lesion appeared almost entirely intramedullary without soft tissue extension; the midfoot lesion demonstrated a destructive, metatarsal-centered bone lesion, initially thought clinically to represent primary bone osteosarcoma. The diagnoses of monophasic synovial sarcoma were rendered via core needle biopsies, with molecular FISH confirmation of SYT gene rearrangement. Clinical follow-up data was only available for the female patient with the primary humeral lesion, who underwent surgical resection, with no local recurrence or distant metastasis at 7 months postsurgery. To our knowledge, these are the first reported examples of molecularly confirmed, primary intraosseous synovial sarcomas of the humerus and metatarsal bones. Primary intraosseous synovial sarcomas with molecular confirmation differ clinically from those lacking it; however, the demographic features and metastatic potential appear similar to primary soft tissue synovial sarcoma.