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.

Rare Primary Embryonal Carcinoma in the Brachial Plexus: A Case Report and Literature Review

BACKGROUND AND IMPORTANCE

Primary tumors of the brachial plexus are rare. Most are benign and characterized as Schwannoma and neurofibroma, whereas malignant peripheral nerve sheath tumors are less common. Here, we report a rare case of primary embryonal carcinoma in the brachial plexus.

CLINICAL PRESENTATION

A 17-yr-old male presented with a 3-mo history of a mass growing in the left supraclavicular region over the middle part of the clavicle. Magnetic resonance imaging revealed a well-defined mass (diameter 2.5 cm) straddling the brachial plexus. After surgical resection, and the mass was histologically confirmed to be an embryonal carcinoma.

CONCLUSION

Primary embryonal carcinoma in the brachial plexus has not been reported previously. This case highlights the importance of considering the possibility that some primary brachial plexus tumors may be malignant and should be treated promptly.

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 mimicking benign peripheral nerve sheath tumor

OBJECTIVE

To assess the radiographic and clinicopathologic features of synovial sarcoma of the nerve that were clinically or radiologically interpreted as benign peripheral nerve sheath tumor.

MATERIALS AND METHODS

Five patients with synovial sarcoma arising from the peripheral nerve and interpreted clinically and radiologically as peripheral nerve sheath tumors were identified. Clinicopathologic and imaging features were evaluated.

RESULTS

There were three females and two males, ranging in age from 28 to 50 (mean 35.8) years. Most patients (4/5) complained of a mass, discomfort or pain. MR images demonstrated a heterogeneous, enhancing, soft tissue mass contiguous with the neurovascular bundle. On histologic examination, most tumors were monophasic synovial sarcoma (4/5). At the time of surgery, all tumors were noted to arise along or within a peripheral nerve. All patients were alive with no evidence of disease with median follow-up of 44 (range 32-237) months. For comparison, approximately 775 benign peripheral nerve sheath tumors of the extremities were identified during the same time period.

CONCLUSIONS

Primary synovial sarcoma of the nerve can mimic peripheral nerve sheath tumors clinically and on imaging and should be included in the differential diagnosis for tumors arising from peripheral nerves.

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.

[Myxoid/round cell liposarcoma of the brachial plexus]

Myxoid/round cell liposarcoma is a soft tissue sarcoma that is extremely rare in the brachial plexus. We report a case of a myxoid/round cell liposarcoma originating in the brachial plexus that was surgically resected and evolved well, with no deficit or recurrence after 2 years of follow-up. To date, there has been no other case of this sarcoma in the literature.