RESUMEN

Melanoma can pose a significant diagnostic challenge due to the high variability in histological morphology and expression of non-melanocytic immunomarkers. We present a case of a 47-year-old male with an aggressive mediastinal neoplasm and disseminated disease posing several diagnostic challenges. Multiple biopsies were submitted from different anatomic locations and during multiple time points showing an undifferentiated round cell tumor (URCT) with synovial sarcoma-like immunophenotype. SS18::SSX fusion was sought through NGS study for diagnostic confirmation. NGS results revealed NRAS and CDKN2A mutations and absence of fusions, resulting in a new review of the histologic material with a broader immunohistochemical panel, finding strong positivity to melanic antibodies. This case is an illustrative example of a malignant melanoma with small round cell morphology showing aberrant expression of CD99, BCL2, TLE1 and SS18-SSX antibodies exposing a potentially hazardous pitfall highlighting the importance of a wide differential diagnosis and the role of confirmational studies with molecular tests.

Asunto(s)

Biomarcadores de Tumor , Inmunofenotipificación , Neoplasias del Mediastino , Melanoma , Sarcoma Sinovial , Humanos , Masculino , Persona de Mediana Edad , Melanoma/patología , Melanoma/diagnóstico , Melanoma/inmunología , Melanoma/genética , Sarcoma Sinovial/patología , Sarcoma Sinovial/genética , Sarcoma Sinovial/diagnóstico , Sarcoma Sinovial/inmunología , Neoplasias del Mediastino/patología , Neoplasias del Mediastino/diagnóstico , Neoplasias del Mediastino/inmunología , Neoplasias del Mediastino/genética , Inmunofenotipificación/métodos , Biomarcadores de Tumor/análisis , Biomarcadores de Tumor/genética , Diagnóstico Diferencial , Proteínas de Fusión Oncogénica/genética , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , GTP Fosfohidrolasas/genética

RESUMEN

The SS18-SSX fusion protein is an oncogenic driver in synovial sarcoma. At the molecular level, SS18-SSX functions as both an activator and a repressor to coordinate transcription of different genes responsible for tumorigenesis. Here, we identify the proto-oncogene FYN as a new SS18-SSX target gene and examine its relation to synovial sarcoma therapy. FYN is a tyrosine kinase that promotes cancer growth, metastasis and therapeutic resistance, but SS18-SSX appears to negatively regulate FYN expression in synovial sarcoma cells. Using both genetic and histone deacetylase inhibitor (HDACi)-based pharmacologic approaches, we show that suppression of SS18-SSX leads to FYN reactivation. In support of this notion, we find that blockade of FYN activity synergistically enhances HDACi action to reduce synovial sarcoma cell proliferation and migration. Our results support a role for FYN in attenuation of anti-cancer activity upon inhibition of SS18-SSX function and demonstrate the feasibility of targeting FYN to improve the effectiveness of HDACi treatment against synovial sarcoma.

RESUMEN

With great interest, we read the article by Manole et al [...].

RESUMEN

Synovialosarcoma is a malignant mesenchymal tumor of young adults that occurs in the deep soft tissues, particularly around large joints. When it occurs in more unusual sites, it could present a significant diagnostic challenge. In this case, a 19-year-old girl was treated for a pyloric mass. A pyelic urine cytology performed simultaneously with a pyloric biopsy proved to be a significant element of orientation and perfectly concordant with the histopathological aspect of the pyelic mass after nephrectomy. We report here the first case of renal synovialosarcoma documented in pyelic urine.

Asunto(s)

Neoplasias Renales , Sarcoma Sinovial , Femenino , Humanos , Adulto Joven , Biopsia , Diagnóstico Diferencial , Neoplasias Renales/patología , Neoplasias Renales/diagnóstico , Nefrectomía , Sarcoma Sinovial/patología , Sarcoma Sinovial/diagnóstico , Orina/citología , Citodiagnóstico/métodos

RESUMEN

We report the clinicopathologic and immunohistochemical features of 18 cases of confirmed primary synovial sarcoma of the gastrointestinal tract. The neoplasms arose in 10 women and 8 men ranging in age from 23 to 81 years (mean: 50; median: 57.5 years). The tumors for which size was known ranged from 1.8 to 15.0 cm (mean: 5.2; median: 5.1 cm). Microscopically, 14 synovial sarcomas were of the monophasic type, 2 were biphasic, and 2 were poorly differentiated. Immunohistochemical analysis of 4 cases showed strong, diffuse staining for SS18::SSX (4/4 cases). Pancytokeratin and EMA immunohistochemistry were performed on 13 and 9 tumors, respectively, and each showed patchy-to-diffuse staining. By reverse-transcription PCR, 3 cases were positive for the SS18::SSX1, and 2 cases were positive for the SS18::SSX2 gene fusion. Six cases contained an SS18 gene rearrangement by fluorescence in situ hybridization, and next-generation sequencing identified an SS18::SSX2 gene fusion in one case. Clinical follow-up information was available for 9 patients (4 months to 4.6 years; mean, 2.8 y; median: 29 months), and one patient had a recent diagnosis. Three patients died of disease within 41 to 72 months (mean, 56 months) of their diagnosis. Five patients were alive without evidence of disease 4 to 52 months (mean, 17.6 months) after surgery; of whom 1 of the patients received additional chemotherapy treatment after surgery because of recurrence of the disease. A single patient was alive with intraabdominal recurrence 13 months after surgery. We conclude that synovial sarcoma of the gastrointestinal tract is an aggressive tumor, similar to its soft tissue counterpart, with adverse patient outcomes. It is important to distinguish it from morphologically similar gastrointestinal tract lesions that may have different treatment regimens and prognoses.

Asunto(s)

Biomarcadores de Tumor , Sarcoma Sinovial , Masculino , Humanos , Femenino , Adulto Joven , Adulto , Persona de Mediana Edad , Anciano , Anciano de 80 o más Años , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/análisis , Sarcoma Sinovial/genética , Sarcoma Sinovial/terapia , Sarcoma Sinovial/diagnóstico , Hibridación Fluorescente in Situ , Proteínas Proto-Oncogénicas/genética , Proteínas de Fusión Oncogénica/genética

RESUMEN

Synovial sarcoma (SS) is a tumor known for its classic monophasic spindle cell or biphasic morphology. However, it exhibits a wide range of histologic variations, leading to diagnostic challenges. Here, we present four cases of molecularly confirmed, biphasic SS originating in the feet and displaying myoepithelial differentiation. The patients were two men and two women with an age range from 19 to 71 years (mean, 45 years). Each tumor showed foci with conventional spindle cell morphology. The epithelial components included areas with nests and cords of epithelioid cells set within a hyalinized and sclerotic stroma. The cytoplasm was clear to pale and eosinophilic. The nuclei were ovoid-round with fine chromatin and small to inconspicuous nucleoli. Mitotic figures were present (2-13 per 10 high-power fields; mean, 6.5). Immunohistochemical studies showed variable staining of the myoepithelial-like regions for low molecular weight keratins, EMA, p63, and S100 protein. Molecular studies confirmed the presence of SS18::SSX1/2 fusion in all four tumors. These cases highlight an unusual variant of synovial sarcoma with an apparent predilection for the distal lower extremity and suggest that differentiation of biphasic synovial sarcoma may be impacted by the anatomic site. Awareness of this variant is important to avoid misclassification and potential treatment and prognostic implications.

RESUMEN

We are reporting a rare case of primary gastric synovial sarcoma in a young male. Synovial sarcoma of the stomach is a very rare tumor. The common involved sites of occurrence of synovial sarcomas are upper and lower extremities. In the English literature, only 47 cases of primary synovial sarcoma of stomach have been reported. Spindle-shaped tumor cells are the basic content of synovial sarcomas with varying degrees of epithelial differentiation. The basic classification of synovial sarcoma depends on the histological pattern and the degree of differentiation and it is classified as monophasic, biphasic, and poorly differentiated. Synovial sarcoma presents with classical chromosomal translocation where they form fusion genes of SS18-SSX1, SS18-SSX2, and SS18-SSX4. Fluorescence in situ hybridization (FISH) and reverse transcription polymerase chain reaction (RT-PCR) are the molecular analysis techniques to detect these fusion genes. As the available literature support is limited, the role of adjuvant chemotherapy, radiation therapy, and intra-operative lymphadenectomy is still unclear. However, surgical resection with clear margin is the gold standard treatment.

RESUMEN

Synovial sarcoma (SyS) is a rare aggressive soft tissue sarcoma carrying the chromosomal translocation t(X;18), encoding the fusion transcript SS18::SSX. The fusion oncoprotein interacts with both BAF enhancer complexes and polycomb repressor complexes, resulting in genome-wide epigenetic perturbations and a unique altered genetic signature. Over 80% of the patients are initially diagnosed with localized disease and have a 5-year survival rate of 70-80%, but metastatic relapse occurs in 50% of the cases. Advanced, unresectable, or metastatic disease has a 5-year survival rate below 10%, representing a critical issue. This review summarizes the molecular mechanisms behind SyS and illustrates current treatments in front line, second line, and beyond settings. We analyze the use of immune check point inhibitors (ICI) in SyS that do not behave as an ICI-sensitive tumor, claiming the need for predictive genetic signatures and tumor immune microenvironment biomarkers. We highlight the clinical translation of innovative technologies, such as proteolysis targeting chimera (PROTAC) protein degraders or adoptive transfer of engineered immune cells. Adoptive cell transfer of engineered T-cell receptor cells targeting selected cancer/testis antigens has shown promising results against metastatic SyS in early clinical trials and further improvements are awaited from refinements involving immune cell engineering and tumor immune microenvironment enhancement.

RESUMEN

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.

Asunto(s)

Sarcoma Sinovial , Sarcoma , Humanos , Masculino , Femenino , Niño , Adolescente , Adulto Joven , Adulto , Persona de Mediana Edad , Anciano , Sarcoma Sinovial/diagnóstico , Sarcoma Sinovial/genética , Sarcoma Sinovial/patología , Sarcoma/patología , Biopsia con Aguja Fina , Biopsia con Aguja Gruesa , Técnicas de Diagnóstico Molecular

RESUMEN

Solid organ malignancies have been reported in survivors of Hodgkin lymphoma treated with chemoradiation; however, to the best of our knowledge no cases of pulmonary synovial sarcoma have been documented in the literature in this cohort. We herein provide a detailed description of synovial sarcoma occurring in the lung of a long-term survivor of childhood Hodgkin lymphoma. A 29-year-old female never smoker with past medical history of Hodgkin lymphoma diagnosed at the age of 7 years and treated with chemotherapy and radiation therapy was admitted for management of pneumothorax. Wedge lung resection of an ulcerated subpleural nodule revealed a malignant spindle cell tumor that based on light microscopic and immunohistochemical features was classified as monophasic synovial sarcoma. The diagnosis was further confirmed by identification of SS18 (SYT) rearrangement by fluorescence in situ hybridization and SS18-SSX1 gene fusion by RNA sequencing. The case documents a rare occurrence of synovial sarcoma in a long-term survivor of childhood Hodgkin lymphoma. While comprising a typical genetic profile for synovial sarcoma, the tumor had unusual histological features such as cystic and low-grade morphology. The case suggests that synovial sarcoma falls within an expanding spectrum of secondary malignancies following prior treatment of Hodgkin lymphoma.

RESUMEN

Primary renal synovial sarcoma is a rare aggressive mesenchymal neoplasm of the kidney that accounts for less than 1% of renal sarcomas. Herein, we describe the clinicopathologic and molecular findings of 14 renal synovial sarcoma patients in one of the largest case series to date and to our knowledge, the only renal synovial sarcoma series to use novel SS18-SSX IHC. Clinicopathologic, IHC, molecular, management, and follow-up data were reviewed and analyzed. Macroscopically, the tumors had either homogeneous, tan-white, and solid (n = 10), variegated and solid (n = 3), or variegated and solid-cystic (n = 1) cut surfaces. Spindle cell (n = 10), round cell (n = 3), and round to epithelioid morphologies (n = 1) were observed. SS18-SSX IHC was positive in all 14 tumors (diffuse, n = 10; multifocal, n = 2; focal, n = 2). All the tumors harbored SS18::SSX1/2 gene rearrangement. Metastases to the liver, brain, and lung (n = 1); liver and bone (n = 1); liver and diaphragm (n = 1) were identified. Adjuvant chemotherapy was administered in 11/12 patients. Follow-up was available for 10 patients (time period range: 5 to 24 months). Four patients died of disease, and six patients are alive with no recurrence or metastasis. As SS18-SSX IHC showed an excellent concordance with the FISH results, this may reliably be used in the IHC panel of spindle/round cell sarcomas of the kidney and as a molecular surrogate for renal synovial sarcoma, particularly in a resource-limited setting. Also, the tumors with focal SS18-SSX expression had lower break apart signals in the FISH assay (19% and 23% in two tumors with focal SS18-SSX IHC positivity).

Asunto(s)

Sarcoma Sinovial , Humanos , Sarcoma Sinovial/diagnóstico , Sarcoma Sinovial/genética , Proteínas de Fusión Oncogénica/genética , Pulmón/patología

RESUMEN

Synovial sarcomas are high-grade soft tissue sarcomas of primitive mesenchymal origin which are defined by a pathognomonic t(X;18)(p11,q11) translocation, and which occur in pediatric and adult populations. Herein we report a case of a 33-year-old female with a history of nasopharyngeal carcinoma status post radiotherapy, presenting with a poorly differentiated synovial sarcoma of the nasal cavity arising in the radiation field. While the development of radiation-associated sarcoma is a known complication of radiotherapy, to date only 10 cases of synovial sarcoma have been reported to occur in previously irradiated tissues. Moreover, only 1 case of poorly differentiated synovial sarcoma involving the nasopharynx has been described.

Asunto(s)

Sarcoma Sinovial , Neoplasias de los Tejidos Blandos , Adulto , Femenino , Humanos , Niño , Sarcoma Sinovial/diagnóstico , Sarcoma Sinovial/patología , Cavidad Nasal/patología , Proteínas de Fusión Oncogénica

RESUMEN

Synovial sarcoma is an aggressive translocation-associated soft tissue tumor driven by an SS18-SSX fusion oncoprotein. TRPS1 is a recently identified marker for breast carcinoma, but less is known about its expression in other tumor types. We encountered a case of synovial sarcoma showing strong and diffuse expression of TRPS1. To better characterize this observation, we examined the immunohistochemical expression of TRPS1 in 165 cases of synovial sarcoma, including 70 primary, 21 recurrent, and 74 metastatic tumors, using tissue microarrays. TRPS1 expression was observed in 86% of cases. Among the positive cases, TRPS1 labeled >50% of tumor cells in 57% of cases, and staining intensity was strong or moderate in 68%. Metastatic tumors more frequently demonstrated strong and diffuse TRPS1 expression compared to primary tumors. To understand the mechanism of TRPS1 expression, we interrogated publicly available gene expression and ChIP-seq datasets and found that TRPS1 transcript levels are increased in synovial sarcoma compared to other soft tissue sarcomas. Data from ChIP-seq experiments showed enrichment of SS18-SSX protein at the TRPS1 locus and co-localization with RNA pol II. The TRPS1 locus is also enriched in several histone modifications associated with active transcription. In functional knockdown data, repression of SS18::SSX in synovial sarcoma cell lines is associated with reduced TRPS1 transcript levels, further supporting a model whereby TRPS1 expression is mediated, at least in part, by the SS18-SSX fusion oncoprotein. Knowledge of TRPS1 expression in synovial sarcoma may help avoid potential diagnostic pitfalls in the immunohistochemical workup of tumors.

Asunto(s)

Sarcoma Sinovial , Neoplasias de los Tejidos Blandos , Humanos , Sarcoma Sinovial/genética , Sarcoma Sinovial/patología , Línea Celular Tumoral , Proteínas de Fusión Oncogénica/genética , Proteínas de Fusión Oncogénica/metabolismo , Translocación Genética , Neoplasias de los Tejidos Blandos/genética , Neoplasias de los Tejidos Blandos/diagnóstico , Proteínas Represoras/genética , Proteínas Represoras/metabolismo

RESUMEN

Prostate synovial sarcoma (SS) is extremely rare. We report a case of prostate SS diagnosed using fine-needle biopsy. The following findings were found: The serum prostate specific antigen level was low, magnetic resonance imaging shows an irregular soft tissue mass in the right posterior part of the prostate, and computed tomography examinations did not reveal any tumor at other parts of the body. Microscopy showed that the tumor cell morphology was densely arranged by interwoven short strands of deep-stained nuclear spindle cells. Immunohistochemical tests were positive for SS18-SSX and SSX. Molecular testing showed that SS18 break-apart Fluorescence In Situ Hybridization (FISH) results were positive, and a comprehensive analysis of this case was performed. Nine cases of prostate SS reported in the English literature were reviewed. In addition, the differential diagnosis, clinical treatment, and clinical prognosis of prostate SS are comprehensively described.

RESUMEN

PURPOSE: Synovial sarcoma (SySa) is a rare soft tissue tumor characterized by a reciprocal t(X;18) translocation. The chimeric SS18-SSX fusion protein represents the major driver of the disease, acting as aberrant transcriptional dysregulator. Oncogenic mechanisms whereby SS18-SSX mediates sarcomagenesis are incompletely understood, and strategies to selectively target SySa cells remain elusive. Based on results of Phospho-Kinase screening arrays, we here investigate the functional and therapeutic relevance of the transcription factor CREB in SySa tumorigenesis. METHODS: Immunohistochemistry of phosphorylated CREB and its downstream targets (Rb, Cyclin D1, PCNA, Bcl-xL and Bcl-2) was performed in a large cohort of SySa. Functional aspects of CREB activity, including SS18-SSX driven circuits involved in CREB activation, were analyzed in vitro employing five SySa cell lines and a mesenchymal stem cell model. CREB mediated transcriptional activity was modulated by RNAi-mediated knockdown and small molecule inhibitors (666-15, KG-501, NASTRp and Ro 31-8220). Anti-proliferative effects of the CREB inhibitor 666-15 were tested in SySa avian chorioallantoic membrane and murine xenograft models in vivo. RESULTS: We show that CREB is phosphorylated and activated in SySa, accompanied by downstream target expression. Human mesenchymal stem cells engineered to express SS18-SSX promote CREB expression and phosphorylation. Conversely, RNAi-mediated knockdown of SS18-SSX impairs CREB phosphorylation in SySa cells. Inhibition of CREB activity reduces downstream target expression, accompanied by suppression of SySa cell proliferation and induction of apoptosis in vitro and in vivo. CONCLUSION: In conclusion, our data underline an essential role of CREB in SySa tumorigenesis and provides evidence for molecular targeted therapies.

Asunto(s)

Sarcoma Sinovial , Animales , Apoptosis , Carcinogénesis , Línea Celular Tumoral , Humanos , Ratones , Proteínas de Fusión Oncogénica/genética , Proteínas de Fusión Oncogénica/metabolismo , Sarcoma Sinovial/tratamiento farmacológico , Sarcoma Sinovial/genética , Sarcoma Sinovial/metabolismo

RESUMEN

BACKGROUND: Synovial sarcomas (SS) are malignant tumors originating from pluripotent mesenchymal cells, with predilection for periarticular areas, as deep-seated soft tissue tumors. Treatment of SS of the head and neck (HN) is usually radical local excision and additional radiation or (neo)adjuvant chemotherapy or both. SS are characterized by a specific SS18-SSX1/2/4 fusion gene. SS have several morphological variants: monophasic, biphasic, or poorly differentiated. METHODS AND RESULTS: We describe a SS of mandibular condyle that showed an overwhelming (>95%) epithelial cell component mimicking odontogenic carcinoma. One year prior to presentation, a woman developed a 2.5 cm destructive bone lesion in the left mandibular condyle. The initial diagnosis of ameloblastoma on biopsy was changed to odontogenic carcinoma on the surgical specimen. Four months later a computed tomography (CT) revealed local recurrence; another month later, magnetic resonance imaging (MRI) depicted a new left temporal lobe brain lesion. The patient started on a carboplatin and paclitaxel therapy, with no clinical or radiologic benefit. Subsequently she was presented for another opinion. The pathology material was re-reviewed. Fluorescence in situ hybridization (FISH) resulted a positive result for SS18 (SYT) rearrangement; next generation sequencing (NGS sarcoma fusion panel) reported an SS18-SSX2 fusion transcript. Based on molecular testing the tumor was reclassified as synovial sarcoma. Her systemic treatment was changed to anthracycline based systemic therapy. CONCLUSIONS: This case emphasizes the importance of molecular approaches in diagnostic pathology. Accurate diagnosis is imperative to avoid misclassification as carcinoma (metastasis or primary e.g., odontogenic carcinoma), carcinosarcoma or a different sarcoma type with epithelioid or epithelial differentiation and to determine proper treatment.

Asunto(s)

Carcinoma , Sarcoma Sinovial , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/metabolismo , Femenino , Humanos , Hibridación Fluorescente in Situ , Proteínas de Fusión Oncogénica/genética , Proteínas Proto-Oncogénicas/genética , Sarcoma Sinovial/diagnóstico , Sarcoma Sinovial/genética , Sarcoma Sinovial/patología , Articulación Temporomandibular/metabolismo , Articulación Temporomandibular/patología

RESUMEN

BACKGROUND: Synovial sarcomas are a rare type of high-grade sarcomas with unknown cell origin. They arise predominantly in the soft tissues but rarely in the stomach. We recently encountered a rare case of minute gastric synovial sarcoma. CASE PRESENTATION: A 61-year-old Japanese woman was pointed out edematous erosion at the body of the stomach. Biopsy specimen showed dense proliferation of spindle-shaped tumor cells mixed with smooth muscle fibers of the muscularis mucosae. Although the definite histological diagnosis was undetermined, the patient underwent laparoscopic wedge resection of the stomach. Histological examination of the resected sample revealed that the maximum diameter of the tumor was only 6 mm and that dense proliferation of rather uniform spindle tumor cells were observed mainly in the submucosa. Immunohistochemistry showed that they were positive for pan-keratin, CD99 and TLE1. SS18-SSX fusion-specific antibody gave diffuse positive staining to the tumor cells, and analysis using mRNA extracted from paraffin sections revealed that the tumor had SS18-SSX1 fusion gene. Thus, it was diagnosed as gastric synovial sarcoma, monophasic fibrous type. CONCLUSIONS: Primary synovial sarcoma of the stomach is rare and only 47 cases have been reported in the English literature to date. The maximum diameter of the lesion of our case was 6 mm which is the smallest among them.

Asunto(s)

Sarcoma Sinovial/patología , Neoplasias Gástricas/patología , Úlcera Gástrica/patología , Biomarcadores de Tumor/análisis , Biomarcadores de Tumor/genética , Femenino , Gastrectomía , Fusión Génica , Humanos , Laparoscopía , Persona de Mediana Edad , Proteínas de Fusión Oncogénica/genética , Sarcoma Sinovial/química , Sarcoma Sinovial/genética , Sarcoma Sinovial/cirugía , Neoplasias Gástricas/química , Neoplasias Gástricas/genética , Neoplasias Gástricas/cirugía , Úlcera Gástrica/cirugía , Resultado del Tratamiento , Carga Tumoral

RESUMEN

BACKGROUND: The novel SS18-SSX fusion-specific antibody is reported to have high sensitivity and specificity for the diagnosis of primary synovial sarcoma (SS), which often metastasizes to the lung. Thus far, no study has validated the diagnostic efficacy of SS18-SSX antibody for pulmonary metastatic SS. Therefore, we aimed to investigate the usefulness of the SS18-SSX antibody in the diagnosis of pulmonary metastatic SS. METHODS: We evaluated the immunohistochemistry of SS18-SSX fusion-specific antibody (E9X9V) in 10 pulmonary metastatic SS cases and the corresponding five primary sites (four limbs and one mediastinum) in five patients, for whom SS was already diagnosed and confirmed by fluorescence in-situ hybridization in the metastatic and primary sites, and in 93 clinical and histologic mimics including 49 non-SS, pulmonary metastatic sarcomas, 39 primary lung cancers, and five intrathoracic solitary fibrotic tumors. All specimens were surgically resected at Shinshu University Hospital during 2001-2019. For primary and metastatic SS, we also evaluated SS18-SSX immunohistochemistry using needle biopsy and touch imprint cytology specimens from the primary site. RESULTS: SS18-SSX staining was diffusely-strongly positive in all 10 pulmonary metastatic SS cases and the corresponding five primary sites; whereas, it was negative in all 93 clinical and histologic mimics (100% sensitivity and 100% specificity). Further, SS18-SSX staining was also sufficiently positive in the biopsy and cytology specimens. CONCLUSIONS: Immunohistochemistry of the SS18-SSX fusion-specific antibody is useful for the differential diagnosis of pulmonary metastatic SS in clinical practice. This simple and reliable method has the potential to replace traditional genomic tests. However, further studies are warranted in this regard.

Asunto(s)

Anticuerpos Monoclonales/inmunología , Biomarcadores de Tumor/análisis , Inmunohistoquímica , Neoplasias Pulmonares/química , Proteínas Proto-Oncogénicas/análisis , Proteínas Represoras/análisis , Sarcoma Sinovial/química , Adulto , Especificidad de Anticuerpos , Biomarcadores de Tumor/inmunología , Diagnóstico Diferencial , Femenino , Humanos , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Proteínas Proto-Oncogénicas/inmunología , Proteínas Represoras/inmunología , Reproducibilidad de los Resultados , Sarcoma Sinovial/secundario

RESUMEN

The recently introduced, highly sensitive and specific SS18-SSX immunohistochemistry (IHC) is an attractive alternative to SS18 fluorescence in situ hybridization (FISH) testing in synovial sarcoma (SS). However, little is known about how SS18-SSX IHC correlates with SS18 FISH. We correlated the SS18 FISH results of SS from 36 patients with SS18-SSX IHC. Twenty-six tumours had a classic break-apart FISH pattern (1 fused, 1 red and 1 green signal) and all stained positive for the IHC. Ten had an atypical (non-classic) FISH pattern of which 5 stained positive for the IHC. Four of these (including two with novel atypical SS18 FISH patterns) were confirmed to harbour the SS18-SSX fusion on targeted RNA sequencing, while one had classic features of a biphasic SS. The remaining 5 tumours stained negative for the IHC. One had a TPM3-NTRK1 fusion, and one had no fusion, while the remaining three had insufficient tissue/RNA for sequencing. The sensitivity of the IHC was 91% (after excluding the 2 cases with confirmed absence of SS18-SSX fusion). Twenty histologic mimics of SS also stained negative for the IHC (100% specificity). Our study shows that the SS18-SSX IHC is more specific than SS18 FISH in diagnosing SS, especially in cases with atypical FISH patterns. It correlates well with RNA sequencing result and has the potential to replace SS18 FISH testing. A positive IHC result supports the diagnosis of SS, while a tumour with atypical FISH pattern and negative IHC result should undergo further molecular testing.

Asunto(s)

Proteínas de Fusión Oncogénica/genética , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Represoras/metabolismo , Sarcoma Sinovial/genética , Adulto , Biomarcadores de Tumor/genética , Femenino , Humanos , Inmunohistoquímica/métodos , Hibridación Fluorescente in Situ/métodos , Masculino , Persona de Mediana Edad , Proteínas Proto-Oncogénicas/inmunología , Proteínas Represoras/genética , Proteínas Represoras/inmunología , Sarcoma Sinovial/inmunología , Sarcoma Sinovial/metabolismo

RESUMEN

Worldwide, 5-10% of soft tissue sarcoma cases in adults have been attributed to synovial sarcoma. It is often reported to occur near the joints of the arm, neck, and leg but rarely in the gastrointestinal tract. In this study, we report a case of synovial sarcoma arising in the stomach of a 59-year-old woman. Gastrointestinal endoscopy revealed an ulcerative and hemorrhagic tumor with marginal elevation in the fundus. Histological study showed that the tumor was composed of tightly packed spindle cells in bundles, and one of its component demonstrated significant mitotic activity (> 40/10 high-power fields) in several areas. The diagnosis was confirmed by the evidence of SS18 gene rearrangement, according to immunohistochemistry study, (including a novel SS18-SSX fusion-specific antibody), fluorescent in situ hybridization, and the identification of the SS18-SSX1 and SS18-SSX1/2/4 fusion transcripts using reverse-transcript polymerase chain reaction. No evidence of local recurrence or distant metastasis has been found in the more than 5 years since. Distinguishing synovial sarcoma in the digestive tract from other mesenchymal neoplasms, such as gastrointestinal stromal tumor, may be difficult, especially when spindle-shaped cell proliferation is predominant, as in our patient. Therefore, morphological, immunohistological, and molecular evaluations are important for a comprehensive diagnosis.

Asunto(s)

Sarcoma Sinovial , Adulto , Biomarcadores de Tumor , Femenino , Humanos , Hibridación Fluorescente in Situ , Persona de Mediana Edad , Recurrencia Local de Neoplasia , Proteínas de Fusión Oncogénica/genética , Sarcoma Sinovial/diagnóstico , Sarcoma Sinovial/genética , Estómago