A rare synovial sarcoma of the spine in the thoracic vertebral body

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.

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.

Tension Pneumothorax: Is it Sarcoma or Pazopanib?

Synovial sarcomas are rare malignant tumors that originate from primitive pluripotent mesenchymal stem cells that look similar to the developing synovium, but are histologically unrelated to it. Sarcomas commonly metastasize to the lungs and surrounding pleura, with a documented incidence as high as 85% for pleural-based metastases. The incidence of spontaneous pneumothorax in patients with sarcomas is only 1.9%, with synovial sarcoma being the third most common type of sarcoma associated with pneumothorax. While surgical resection is usually the treatment for localized primary synovial cell sarcoma, metastatic disease requires systemic therapy, mainly chemotherapy. Failure of chemotherapy calls for the use of targeted therapeutic agents such as pazopanib. Pazopanib has been linked to the incidence of spontaneous pneumothorax in previous case studies. However, primary research fails to establish a statistically significant causal association. Research shows that pneumothorax can result from lung metastases independent of therapeutic side effects. We report a case of synovial sarcoma of trapezius origin with secondary lung metastases, and development of pneumothorax after pazopanib treatment. We discuss the incidence of pneumothorax as a medication side effect versus independent effect of natural disease progression, and how this plays role in deciding when to continue using a medication in the face of complications.

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.

Total en bloc resection of primary and metastatic spine tumors

Primary and metastatic tumors of the spine represent a significant cause of patient morbidity, and present a management challenge to treating providers. From a neurosurgical standpoint, resection surgery may be warranted in cases of spinal instability, progressive disease, neurological compromise, or intractable symptoms. Removal of a tumor "en bloc" offers a more aggressive modality over more conservative resection techniques. En bloc resection entails the removal of the entirety of a tumor without violation of its capsule, and may offer improved rates of local control and overall survival in appropriately selected patients. Conversely, this technique carries a higher complication rate, and requires a unique set of technical skills as compared to more traditional resection. Here, we describe the technical aspects of en bloc resection, as well as specific indications and considerations when employing this operative technique.

Intraosseous synovial sarcoma of the distal ulna: a case report and review of the literature

Background

Synovial sarcoma is a relatively rare type of soft tissue sarcoma. The commonly observed symptom is a deep-seated palpable mass accompanied by pain or tenderness. Thus, it is considered a soft tissue sarcoma and rarely occurs primarily in bone. However, only few studies have been reported on intraosseous synovial sarcoma, and reports on cases with cytogenetic or molecular confirmation are even rarer. We report a case of intraosseous synovial sarcoma of the distal ulna that has been confirmed using histopathological examination and molecular analysis.

Case presentation

A 77-year-old female was referred to our hospital with a 1-month history of right wrist pain after housework. Clinical and imaging findings suggested a benign bone tumor that was enhanced by Gd-DTPA. It was thought that the tumor was possibly an enchondroma. Initially, we planned to evaluate the benignancy of the tumor with intraoperative frozen section, followed by curettage and bone graft at one stage However, when considering carefully, characteristics of the tumor did not perfectly match those of any diagnostic categories including enchondroma. Therefore, an incisional biopsy was performed and revealed that the tumor was synovial sarcoma. Following an elaborate plan, the patient underwent a wide resection of the tumor at the distal part of the right ulna. Reverse transcription-polymerase chain reaction (RT-PCR) from the resected specimen and sequencing of RT-PCR products demonstrated a chimeric SYT-SSX1 transcript, confirming the diagnosis of synovial sarcoma.

Conclusions

Synovial sarcoma is seldom considered in differential diagnosis of bone tumors because it is difficult to line up such an unusual diagnosis as a differential diagnosis. When the lesion does not perfectly fit into any diagnostic category, when the initial image diagnosis appears unconvincing, biopsy and pathology are indicated, recalling Jaffe’s triangle. According to these diagnostic processes, the patient successfully completed the treatment for this rare intraosseous synovial sarcoma, following a careful plan based on the preoperative diagnosis.

Surgical management and outcome of synovial sarcoma in the spine

Background

Synovial sarcoma (SS) is a soft tissue sarcoma that rarely occurs in the spine, and a minimal number of cases have been reported in the literature. Spinal SS is challenging in diagnosis and treatment and has a poor prognosis. The aim of this study was to summarize and analyse the clinical features and outcomes of patients with spinal SS.

Methods

A total of 16 cases of patients with spinal SS admitted to our institution were reviewed retrospectively. General information, radiological findings and treatment strategies were collected. These patients were followed up regarding their continuing treatment, local or distant recurrence and survival.

Results

Spinal SS patients in this series ranged in age from 12 to 68 years (median, 33). Four en bloc resections and 12 piecemeal resections were performed. Improved Frankel (P = 0.002), visual analogue scale (P = 0.002) and Karnofsky Performance Status (P = 0.002) scores were seen postoperatively. The mean follow-up period was 35.9 ± 23.5 (median 31.5, range 4–87) months, with four local recurrences and three distant metastases detected. Eight patients (50.0%) died of disease by the last follow-up. The 1-, 3- and 5-year overall survival rates were 87.5%, 61.4% and 40.9%, respectively. Preoperative chemotherapy was used in three patients to facilitate surgical resection, and adjuvant chemotherapy and radiotherapy were used in six patients.

Conclusions

Spinal SS has a relatively high risk of local recurrence and distant metastasis. Surgical intervention can improve the neurological function and relieve pain in these patients. En bloc excision is an effective treatment strategy to improve survival and prevent local recurrence. Management of spinal SS should be under the instruction of a multidisciplinary team.