Cytologic features of primary monophasic synovial sarcoma of the thyroid gland

Synovial sarcoma: characteristics, challenges, and evolving therapeutic strategies

Synovial sarcoma (SS) is a rare and aggressive disease that accounts for 5%-10% of all soft tissue sarcomas. Although it can occur at any age, it typically affects younger adults and children, with a peak incidence in the fourth decade of life. In >95% of cases, the oncogenic driver is a translocation between chromosomes X and 18 that leads to the formation of the SS18::SSX fusion oncogenes. Early and accurate diagnosis is often a challenge; optimal outcomes are achieved by referral to a specialist center for diagnosis and management by a multidisciplinary team as soon as SS is suspected. Surgery with or without radiotherapy and/or chemotherapy can be effective in localized disease, especially in children. However, the prognosis in the advanced stages is poor, with treatment strategies that have relied heavily on traditional cytotoxic chemotherapies. Therefore, there is an unmet need for novel effective management strategies for advanced disease. An improved understanding of disease pathology and its molecular basis has paved the way for novel targeted agents and immunotherapies that are being investigated in clinical trials. This review provides an overview of the epidemiology and characteristics of SS in children and adults, as well as the patient journey from diagnosis to treatment. Current and future management strategies, focusing particularly on the potential of immunotherapies to improve clinical outcomes, are also summarized.

Primary synovial sarcoma of the thyroid gland: a CARE compliant case report and literature review

Rationale

Synovial sarcoma is a subtype of soft tissue sarcoma. Synovial sarcoma in the head and neck region is relatively unusual. Primary synovial sarcoma of the thyroid gland (PSST) is first reported in 2003 by Inako Kikuchi. PSST is extremely rare with only 15 cases documented globally. PSST shows rapid disease progression and a relatively poor prognosis. However, diagnosis and therapy are challenging for clinical surgeons. In this article, we reported the 16th PSST case and reviewed the PSST cases globally for further clinical application.

Patient concerns

The patient was referred to us because of gradually worsened dyspnea and dysphagia for 20 days. Physical examination showed a 5 × 4 cm mass with a clear boundary and good mobility. Contrast-enhanced ultrasonography (CEUS) and computed tomography (CT) showed a mass in the isthmus of the thyroid gland. The imageology diagnosis tends to be a benign thyroid nodule.

Diagnosis

After surgery, histopathology, immunohistochemistry, and fluorescence, in situ hybridization indicated the mass to be primary synovial sarcoma of the thyroid gland with no local and distant metastasis.

Interventions

The patient underwent total thyroidectomy and dissected the lymph nodes in the central compartment. This patient received postoperative chemotherapy (a combination of ifosfamide and epirubicin for five cycles). Patients tolerated chemotherapy well. No recurrence was found during the 9-month follow-up.

Lessons

Although PSST is an extremely rare disease, we should raise our awareness when we encounter a rapidly growing, cystic-solid mixed thyroid mass with neck compression symptoms to avoid misdiagnosis. Intraoperatively, surgeons should refine surgical procedures to avoid capsular rupture and tumor local implantation metastasis. Intraoperative frozen section pathology is necessary sometimes, especially when the diagnosis could not be established before surgery.

Synovial sarcoma: cytopathology of 51 cases highlighting the application of ancillary molecular testing

INTRODUCTION

Among sarcomas, synovial sarcoma (SS) is defined by its unique SS18 cytogenetic translocation. Fine needle aspiration (FNA) biopsy is in a key position to exploit this uniqueness for diagnostic purposes.

MATERIALS AND METHODS

Our cytopathology files were searched for examples of SS with histopathologic verification. FNA biopsy, imprint smears, and core needle biopsy (CNB) were performed using standard techniques.

RESULTS

Fifty-one cases from 49 patients (male/female ratio, 1:1; age range, 12-79 years; mean age, 40 years) met the inclusion criteria. Of the 51 cases, 44 (86%) were FNAs, 6 were cytology imprints, and 1 was pleural fluid. Eleven aspirates had concurrent CNB. All cases had tissue confirmation. The biopsy sites included extremities (n = 24; 47%), trunk (n = 12; 24%), lung (n = 8; 16%), head or neck (n = 6; 12%), and pleural fluid (n = 1; 2%). The aspirates were from primary (n = 36; 71%), metastatic (n = 12; 24%), and recurrent (n = 3; 5%) neoplasms. The cytologic diagnoses were SS (69%), suspicious for SS (12%), malignancy (10%), spindle cell neoplasm (4%), and malignancy other than SS (6%). In general, smears and imprints contained dense cell aggregates and single cells composed of a monotonous population having fusiform, rounded, or ovoid banal nuclei and scant cytoplasm. Poorly differentiated SS showed both large epithelioid cell and small cell cytomorphology. When performed, SS18 immunohistochemical and genetic testing was positive in all 19 FNA and 3 CNB cases.

CONCLUSIONS

When coupled with appropriate ancillary testing, FNA biopsy allows for a specific, accurate diagnosis of SS in most cases.

Case Report of Primary Synovial Sarcoma of the Thyroid Gland: An Unusual Histology at Atypical Location

Primary synovial sarcoma of the thyroid gland is extremely rare, aggressive, and has a dismal prognosis. We report the case of a 15-year-old male who presented with a progressively increasing neck mass, which was excised and the histopathological and immunohistochemical study suggested biphasic synovial sarcoma of the thyroid gland which was confirmed by synovial sarcoma translocation. There are 14 cases of primary synovial sarcoma of the thyroid reported in the literature so far. This study aimed to document the occurrence of synovial sarcoma histology at an unusual anatomical location with a review of the literature on this rare entity.

Extensive spindling in medullary thyroid carcinoma posing a diagnostic challenge: A case report

Medullary thyroid carcinoma is a neuroendocrine tumor derived from parafollicular or 'C' cells with sporadic and familial forms. Fine needle aspiration cytology is a quick way to establish the diagnosis. Sometimes a usual tumor may show prominent spindling on cytomorphology due to sampling issues, which poses a diagnostic challenge. When encountering spindled tumor cells on cytology smears from the thyroid, differential diagnoses encompass many benign and malignant lesions. We present cytological findings of the usual type of medullary thyroid carcinoma showing extensive spindling on cytology smears, which was a diagnostic dilemma. An accurate diagnosis was reached with the judicious use of immunocytochemistry on the cell block. We also discuss the available literature, differential diagnoses, and how to troubleshoot.

Synovial sarcoma of the head & neck: A review of reported cases in the literature

Synovial sarcoma is a high-grade malignancy that seldom manifests in the head and neck. The purpose of this paper is to provide a comprehensive review of the existing literature on primary HNSS. This review study includes case reports, case series and retrospective cohort studies on primary HNSS published in the English language. All cases identified via PubMed were analyzed individually. Articles were included according to specified eligibility criteria. The total number of cases analyzed was 243 (91 case reports, 53 cases from 16 case series, and 99 cases from 8 retrospective cohort studies). The average age at the time of HNSS diagnosis was 33.5 years. The ratio of male-to-female was 1.64:1. The most frequently occurring histologic subtype was biphasic (59.2%). The most common location was the neck. Hoarseness was the most common presenting symptom. Almost all patients (98.3%) underwent surgical excision. 55.6% of patients received adjuvant radiotherapy. A smaller number of patients (30.7%) received adjuvant chemotherapy. 60.3% of patients were alive with no evidence of disease at follow-up while 28.0% of patients died of HNSS at follow-up. The average follow-up period was 52.0 months. Synovial sarcoma is a rare head and neck malignancy. Surgical excision with adjuvant radiation is the most frequently employed treatment modality. Regardless of treatment modality, the prognosis of the tumor is guarded.

Intracranial synovial sarcoma: A clinical, radiological and pathological study of 16 cases

INTRODUCTION

Synovial sarcoma (SS) is a tumor of unknown origin and is extremely rare in the central nervous system. Most studies on intracranial SS included only one or two cases. To better understand the disease, we review a series of primary intracranial SS.

METHOD AND MATERIALS

16 primary intracranial SS in Tiantan Hospital during 2008-2017 were included. The clinical characteristics, including radiological and histological examination, operative records, and prognoses were reviewed.

RESULT

The case series included nine male and seven female patients with an average age of 23.8 years. Radiological results showed that the supratentorial region (81.25%) was the most common site of the brain involved. All patients were misdiagnosed as non-SS tumors. Gross total resection (GTR) was achieved in 12 cases (75.0%), and subtotal resection (STR) was achieved in 4 cases. All cases showed the characteristic SYT-SSX fusion gene, as detected by RT-PCR. The mean progression-free survival time (PFS) was 10.0 months and the mean overall survival time (OS) was 15.5 months. Multivariate analysis revealed that GTR and postoperative adjuvant radiotherapy were independent factors for PFS (HR = 6.143, 95% CI = 1.491-25.312; P = 0.012, HR = 6.143, 95% CI = 1.491-25.312; P = 0.012 respectively) and OS (HR = 9.000, 95% CI = 1.627-49.773; P = 0.012, HR = 0.017, 95% CI = 0.001-0.213; P = 0.002 respectively).

CONCLUSION

Intracranial SS were more frequently observed in the supratentorial region and in young patients without sex predilection. We recommend adjuvant radiation regardless of the extent of resection. More patients and longer follow-up periods were needed to further elucidate the biological features of intracranial SS.

From fine-needle aspiration cytology to fluorescent in-situ hybridization in an unusual case of pharyngeal synovial sarcoma

Synovial sarcoma arising in the pharynx is a rare entity, with very few cases described in literature, mainly as surgical-oriented case reports. We report the case of a healthy 20-year old man who presented with a painless right neck mass, clinically suspicious for a thyroid nodule. Ultrasound scan and fine-needle aspiration cytology failed to provide a definitive result, although suggesting a mesenchymal proliferation, in accordance with magnetic resonance imaging findings. Therefore, the lesion was removed with a minimally invasive surgical intervention. Definitive histologic and immunohistochemical examination of the surgical specimen revealed a biphasic synovial sarcoma, further validated by the detection of SS18 gene rearrangement on fluorescent in-situ hybridization examination. Although rarely, synovial sarcoma may arise in the pharynx. Radiological, cytological, histological and molecular findings are needed along each step of the diagnostic process.