Primary monophasic synovial sarcoma of the brachial plexus: report of a case and review of the literature

Monophasic synovial sarcoma mimicking schwannoma: a case report of a rare peripheral nerve tumor and literature review

INTRODUCTION

Synovial sarcomas occurring as primary nerve tumors (SSPN) are rare and only 69 cases of SSPNs are reported in literature. Despite the little data available, SSPNs differ from other SSs in some distinctive aspects such as epidemiology, location, and early onset of symptoms. SSPN are consequently underdiagnosed and easily mistaken for benign or malignant peripheral nerve sheath tumors (PNST). Therefore, cytogenetic or molecular testing becomes essential in order to make a correct diagnosis. This article deals with an extremely rare case of monophasic SSPN of the posterior cords of the right brachial plexus. To our knowledge, this is only the tenth case of intraneural synovial sarcoma involving the brachial plexus.

CASE PRESENTATION

We report the case of a 64-year-old man, who came to our attention due to a slow-growing painful right axillary neoformation, approximately 25 mm in size. The patient did not show any neurological impairments. Ultrasonography and constrast MRI showed a heterogeneous mass arising from the posterior cord of the right brachial plexus, resembling a schwannoma. The patient underwent total resection of tumor and capsule. Histologically, a diagnosis of monophasic synovial sarcoma was made based on histologic features and the immunohistochemical profile.

CONCLUSIONS

We report a rare primary synovial sarcoma of the brachial plexus. Given its rarity, the diagnosis may be challenging and requires a core biopsy or the surgical specimen to permit immune-molecular analysis. Margin-free surgery is the mainstay of curative treatment, while chemo- or radiotherapy may have a role in advanced or margin-positive neoplasms.

Synovial Sarcoma of the Nerve-Clinical and Pathological Features: Case Series and Systematic Review

BACKGROUND

Synovial sarcoma of the nerve is a rare entity with several cases and case series reported in the literature. Despite an improved understanding of the biology, the clinical course is difficult to predict.

OBJECTIVE

To compile a series of patients with synovial sarcoma of the peripheral nerve (SSPN) and assess clinical and pathological factors and their contribution to survival and recurrence.

METHODS

Cases from 2 institutions collected in patients undergoing surgical intervention for SSPN. Systematic review including PubMed and Scopus databases were searched for related articles published from 1970 to December 2018. Eligibility criteria: (1) case reports or case series reporting on SSPN, (2) clinical course and/or pathological features of the tumor reported, and (3) articles published in English.

RESULTS

From patients treated at our institutions (13) the average follow-up period was 3.2 yr. Tumor recurrence was seen in 4 cases and death in 3. Systematic review of the literature yielded 44 additional cases with an average follow-up period of 3.6 yr. From pooled data, there were 10 recurrences and 7 deaths (20% and 14%, respectively). Adjuvant treatment used in 62.5% of cases. Immunohistochemical markers used in diagnosis varied widely; the most common are the following: Epithelial membrane antigen (EMA), cytokeratin, vimentin, cluster of differentiation (CD34), and transducin-like enhancer of split 1 (TLE1). Statistical analysis illustrated tumor size and use of chemotherapy to be negative predictors of survival. No other factors, clinically or from pathologist review, were correlated with recurrence or survival.

CONCLUSION

By combining cases from our institution with historical data and performing statistical analysis we show correlation between tumor size and death.

Synovial sarcoma of the brachial plexus - a rare tumor in a rare area: a case report

Background

Synovial cell sarcomas are usually seen in a juxta-articular location. However, they occur rarely in the head and neck region.

Case presentation

We report a rare case of brachial plexus synovial sarcoma in a 24-year old South Asian man treated successfully with surgical excision followed by radiotherapy.

Conclusions

Synovial sarcoma arising from the brachial plexus is rare. The treatment is multimodal with complete excision (often challenging owing to the proximity of the neurovascular structures) and adjuvant therapy.

Synovial Sarcoma of Peripheral Nerves: Analysis of 15 Cases

Synovial sarcoma of peripheral nerve (SSPN) is rare with only 26 cases reported in English. SSPN is often mistaken for a benign or malignant peripheral nerve sheath tumor (PNST) by clinicians and pathologists. Fifteen cases of SSPN were retrieved from the pathology files of 3 institutions. All tumors arose in a nerve based on imaging and/or operative findings and the diagnoses were histologically confirmed. Neuropathic symptoms predominated in 11 women and 4 men, 19- to 62-year-old (median, 39 years) with tumors involving the ulnar (5), median (3), peroneal (3) or sciatic (2) nerve, or the L4 or T1 nerve root (2). Tumor sizes ranged from 2 to 13 cm (median, 3.8 cm). The leading clinical diagnosis was PNST (9). Treatment was surgical (14) supplemented with radiation therapy (8) and chemotherapy (6). Fourteen tumors were monophasic and 1 was biphasic; 4 had poorly differentiated (PD) foci (1 rhabdoid). Diagnoses in 12 cases were verified by fluorescence in situ hybridization, reverse transcription polymerase chain reaction or both methods. Follow-up in 14 patients (median, 32 mo) revealed that 2/4 patients with PD tumors died with pulmonary metastases; another was alive with no current evidence of disease (NED) following 2 local recurrences, while the fourth had NED. In contrast, 9/10 patients without PD tumors were alive (7 NED) and 1 died at 12 months with pulmonary infiltrates. SSPN is under-recognized clinically and histologically as it mimics benign and malignant PNST. Molecular analysis is recommended to confirm the diagnosis. PD foci, including rhabdoid areas, may portend a worse outcome, similar to non-neural-based tumors.

Primary Brachial Plexus Tumors: Clinical Experiences of 143 Cases

OBJECTIVE

Primary brachial plexus tumors are extremely rare and the treatment is challengeable. Our aim is to share the experiences in the treatment of primary brachial plexus tumors.

METHODS

A retrospective analysis of 143 patients with primary brachial plexus tumors was made in our department from January 2001 to December 2012. The clinical presentation of the patients, the characteristics and pathological results of the tumors and the prognosis were described.

RESULTS

Seventy-eight males and sixty-five female were enrolled. The mean age was 48.17 years old. A palpable mass was the most common clinical presentation occurred in 129 patients. The trunks of the brachial plexus were the locations where the tumors originated with high possibility, with 68 cases. Benign tumors were composed of 119 schwannomas and 12 neurofibromas, while malignant tumors were composed of 8 malignant peripheral nerve sheath tumors, 2 malignant granular cell tumors, 1 synovial sarcoma and 1 peripheral primitive neuroectodermal tumor. Appropriate surgical method, radiotherapy and chemotherapy were used according to the condition during operation, preoperative examinations and pathological result. The survival rate was 50.00% with a 3-year follow-up. Local recurrence happened in 7 patients. Five patients presented Metastasis.

CONCLUSIONS

Appropriate surgical method is the key for the treatment of different brachial plexus tumors. Surgery has a great effect on the treatment of benign tumors. For malignant tumors, adjuvant radiotherapy or chemotherapy should be used according to the pathological result. The general prognosis for malignant brachial plexus tumors is less than ideal.

Pediatric primitive intraneural synovial sarcoma of L-5 nerve root

Primitive intraneural synovial sarcomas are rare in children. The authors report the case of a 7-year-old girl affected by intraneural synovial sarcoma of a lumbar nerve root, the first such lesion in this location described in a child. The lesion mimicked a schwannoma clinically and radiologically. There was long-lasting leg pain in a radicular distribution, and a well-demarcated intraneural tumor was seen on MRI. On this basis, the first resection was conservative. However, histological examination documented a classic biphasic synovial sarcoma, which was confirmed by immunohistochemistry. After radical resection and adjuvant treatment, complete disease control was achieved and verified at 5-year follow-up. This case strongly suggests that early diagnosis and a multidisciplinary approach to this unusual spinal lesion are essential to achieving a better prognosis.

Synovial Sarcoma of the Brachial Plexus

BACKGROUND AND IMPORTANCE:

Synovial sarcoma (SS) is a malignant soft-tissue tumor that rarely involves brachial plexus. The authors report a case of brachial plexus SS and review the relevant literature.

CLINICAL PRESENTATION:

A 53-year-old woman presented with gradually enlarging right subclavicular mass over 5 years associated with sharp aching pain radiating down toward the radial 3 fingers. On examination, she had a corresponding firm mass in the supraclavicular region with a positive Tinel sign. There was no objective neurological deficit. She underwent partial excision of this mass without any further adjuvant radiation or chemotherapy. Pathology was consistent with SS.

CONCLUSION:

Lack of any recurrence in this case 6 years after incomplete excision with no adjuvant therapy suggests slow clinical course in some of these sarcomas.

Synovial sarcoma of nerve

Tumors of peripheral nerve are largely neuroectodermal in nature and derived from 2 elements of nerve, Schwann or perineurial cells. In contrast, mesenchymal tumors affecting peripheral nerve are rare and are derived mainly from epineurial connective tissue. The spectrum of the latter is broad and includes lipoma, vascular neoplasms, hematopoietic tumors, and even meningioma. Of malignant peripheral nerve neoplasms, the vast majority are primary peripheral nerve sheath tumors. Malignancies of mesenchymal type are much less common. To date, only 12 cases of synovial sarcoma of nerve have been described. Whereas in the past, parallels were drawn between synovial sarcoma and malignant glandular schwannoma, an uncommon form of malignant peripheral nerve sheath tumor, molecular genetics have since clarified the distinction. Herein, we report 10 additional examples of molecularly confirmed synovial sarcoma, all arising within minor or major nerves. Affecting 7 female and 3 male patients, 4 tumors occurred in pediatric patients. Clinically and radiologically, most lesions were initially thought to be benign nerve sheath tumors. On reinterpretation of imaging, they were considered indeterminate in nature with some features suspicious for malignancy. Synovial sarcoma of nerve, albeit rare, seems to behave in a manner similar to its more common, soft tissue counterpart. Those affecting nerve have a variable prognosis. Definitive recommendations regarding surgery and adjuvant therapies await additional reports and long-term follow-up. The literature is reviewed and a meta-analysis is performed with respect to clinicopathologic features versus outcome.

Intraneural synovial sarcoma of the median nerve

Synovial sarcomas are soft-tissue malignancies with a poor prognosis and propensity for distant metastases. Although originally believed to arise from the synovium, these tumors have been found to occur anywhere in the body. We report a rare case of synovial sarcoma arising from the median nerve. To our knowledge, this is the twelfth reported case of intraneural synovial sarcoma, and only the fourth arising from the median nerve. Because the diagnosis may not be apparent until after pathological examination of the surgical specimen, synovial sarcoma should be kept in mind when dealing with what may seem like a benign nerve tumor.

Management of brachial plexus region tumours and tumour-like conditions: relevant diagnostic and surgical features in a consecutive series of eighteen patients

BACKGROUND

Tumours of the brachial plexus region are rare and most publications are case reports or studies with a small series of patients. The aim of this study is to present our experience in managing these lesions.

METHODS

We review 18 patients with tumours in the brachial plexus region submitted to surgical treatment in a 6 year period, including their clinical presentation, neuro-imaging data, surgical findings and outcome.

FINDINGS

The tumours comprised a heterogeneous group of lesions, including schwannomas, neurofibromas, malignant peripheral nerve sheath tumour (MPNST), sarcomas, metastases, desmoids and an aneurysmal bone cyst. The most common presentation was an expanding lump (83.33%). Eleven tumours were benign and 7 were malignant. Neurofibromatosis was present in only 2 patients (11.11%). Gross total resection was achieved in 14 patients and sub-total resection in the others. Only 3 patients presented with new post-operative motor deficits. The incidence of complications was low (16.5 %).

CONCLUSIONS

The majority of tumours were benign and most of them could be excised with a low incidence of additional deficits. Some of the malignant tumours could be controlled by surgery plus adjuvant therapy, but this category is still associated with high morbidity and mortality rates.

Monophasic synovial sarcoma of the pharynx: a case report

Synovial sarcomas are a rare form of soft tissue sarcomas. We present a case of a 62 year-old male presenting with a left thyroid lump initially though to be a thyroid adenoma but subsequently diagnosed as a monophasic synovial sarcoma of the pharynx. We discuss the diagnosis and treatment of this case.

Cervical nerve root synovial sarcoma in a child with chromosomal (X;18) translocation. Case report and review of the literature

We report on an 11-year-old female with a history of cervicobrachialgia and progressive weakness of the right arm. Cervical spine MRI showed an enhancing heterogeneous intradural mass occupying the right C6-C7 foramen. She underwent a right C6-C7 foraminotomy with a complete macroscopic removal of the lesion. Pathological examination revealed a synovial sarcoma. Treatment was completed by chemotherapy and proton radiotherapy, and the girl remained free of symptoms for 3 years. After appearance of new symptoms, a local recurrence was confirmed, and despite aggressive treatment with salvage chemotherapy and radiotherapy, the disease progressed beyond medical control, and the child died, 6 years after diagnosis. Early recognition of this rare entity compared to its more benign differential diagnosis is crucial, as an aggressive management is needed.

Intraneural monophasic synovial sarcoma: a case report

STUDY DESIGN

A case report.

OBJECTIVES

To illustrate a rare case of synovial sarcoma arising within a peripheral nerve.

SUMMARY OF BACKGROUND DATA

A synovial sarcoma arising within a peripheral nerve is very unusual. Only five cases of primary synovial sarcoma within a peripheral nerve have been reported. This is the first case with involvement of the nerve root. The authors diagnosed the tumor arising within the S1 nerve root as synovial sarcoma using cytogenetic analysis that detected the chimeric SYT/SSX gene.

METHODS

In addition to the immunohistochemical study, a reverse transcription-polymerase chain reaction (RT-PCR) assay was conducted for the SYT-SS10 fusion gene using archival formalin-fixed paraffin-embedded tumor specimens.

RESULTS

Computed tomography scan, magnetic resonance imaging performed before surgery, and the intraoperative findings showed that the tumor was embedded within the S1 nerve root. Although the histologic findings were suggestive of a malignant peripheral nerve sheath tumor, the results of the cytologic study confirmed its diagnosis of synovial sarcoma.

CONCLUSION

Primary intraneural synovial sarcoma, although rare, must be distinguished from malignant peripheral nerve sheath tumor. The molecular assay of the detection of the SYT/SSX fusion gene is useful to make a definite diagnosis of monophasic synovial sarcoma.