FDG PET/CT and MRI Findings of Extraskeletal Myxoid Chondrosarcoma Showing a Nonmyxoid Cellular Variant.

ABSTRACT: We present a new, extremely rare nonmyxoid cellular variant of extraskeletal myxoid chondrosarcoma. Although diagnosis is radiologically and pathologically challenging, FDG PET/CT and MRI accurately showed the malignancy and high tumor density. A 52-year-old woman complained of a left dorsal mass, which presented inhomogeneous intermediate signals on T2-weighted images, with diffusion restriction, strong enhancement, and increased accumulation of FDG (SUV max , 5.2). Although biopsy was inconclusive, a highly malignant tumor was suspected radiologically. The resected specimen was histologically diagnosed as extraskeletal myxoid chondrosarcoma by detection of EWSR1::NR4A3 fusion using fluorescence in situ hybridization.

Extraskeletal myxoid chondrosarcoma metastasis to a Meckel's diverticulum adenocarcinoma.

Extraskeletal myxoid chondrosarcoma is a rare soft tissue tumour with a high local and distant metastasis rate and limited response to chemotherapy. Meckel's diverticulum is the most frequent congenital anomaly, and it is associated with a considerable risk of malignant transformation. In this case report, we describe a 50-year-old female patient with a history of extraskeletal myxoid chondrosarcoma of the lower limb and metastasis to the forearm who went to the emergency department with abdominal pain. The investigations revealed a caecal volvulus. A lesion in the middle third of the ileum was incidentally discovered and removed during surgery. Pathology examination revealed a Meckel's diverticulum adenocarcinoma, with metastasis of extraskeletal myxoid chondrosarcoma. Resection was complete; however, the patient had diffuse metastatic pulmonary disease and died eight months later due to disease progression. This mechanism of tumour-to-tumour metastasis is described in other locations, but, regarding the Meckel's diverticulum, this is a unique situation, previously unreported in the literature.

Endobronchial solitary fibrous tumors: An enigma for diagnosis.

Solitary fibrous tumors (SFTs) are rare mesenchymal neoplasms constituting less than 2% of all soft tissue tumors. They typically originate in the thoracic cavity, mainly in the pleura, but can also occur in other various sites such as lung parenchyma, pericardium, and bronchus. In this study, a 49-year-old non-smoking female with a history of allergies presented to our pulmonary clinic with a chronic cough. An explorative bronchoscopy revealed an intrabronchial mass in the left superior bronchi, and a 68 Ga-DOTATOC positron emission computed tomography suggested a carcinoid tumor. Subsequent pulmonary segmentectomy unveiled a well-circumscribed polypoid lesion diagnosed as a low-grade bronchus SFT through histopathological and immunohistochemical assessments. The patient was asymptomatic after surgical excision and showed no other lesion during the 6-month follow-up. The endobronchial location of SFT is uncommon, with only a few reported cases in the literature, underscoring the necessity of considering various differential diagnoses, including carcinoid, mucoepidermoid carcinoma, endobronchial pleomorphic adenoma, hamartoma, leiomyoma, and metastasis, depending on location and imaging features. This report underscores the importance of careful histological and immunohistochemical evaluation in understanding and appropriately stratifying the risk associated with polypoid lesions.

Spindle cell neoplasms with novel LTK fusion - Expanding the spectrum of kinase fusion-positive soft tissue tumors.

AIMS: Kinase fusion-positive soft tissue tumors represent an emerging, molecularly defined group of mesenchymal tumors with a wide morphologic spectrum and diverse activating kinases. Here, we present two cases of soft tissue tumors with novel LTK fusions. METHODS AND RESULTS: Both cases presented as acral skin nodules (big toe and middle finger) in pediatric patients (17-year-old girl and 2-year-old boy). The tumors measured 2 and 3 cm in greatest dimension. Histologically, both cases exhibited bland-looking spindle cells infiltrating adipose tissue and accompanied by collagenous stroma. One case additionally displayed perivascular hyalinization and band-like stromal collagen. Both cases exhibited focal S100 staining, and one case had patchy coexpression of CD34. Targeted RNA-seq revealed the presence of novel in-frame MYH9::LTK and MYH10::LTK fusions, resulting in upregulation of LTK expression. Of interest, DNA methylation-based unsupervised clustering analysis in one case showed that the tumor clustered with dermatofibrosarcoma protuberans (DFSP). One tumor was excised with amputation with no local recurrence or distant metastasis at 18-month follow-up. The other case was initially marginally excised with local recurrence after one year, followed by wide local excision, with no evidence of disease at 10 years of follow-up. CONCLUSIONS: This is the first reported case series of soft tissue tumors harboring LTK fusion, expanding the molecular landscape of soft tissue tumors driven by activating kinase fusions. Furthermore, studies involving a larger number of cases and integrated genomic analyses will be warranted to fully elucidate the pathogenesis and classification of these tumors.

CHRNA6 RNA In Situ Hybridization Is a Useful Tool for the Diagnosis of Extraskeletal Myxoid Chondrosarcoma.

Extraskeletal myxoid chondrosarcoma (EMC) is an uncommon mesenchymal neoplasm characteristically composed of uniform-appearing round to spindle-shaped cells with eosinophilic cytoplasm and abundant myxoid extracellular matrix. Although the majority of cases harbor a pathognomonic t(9;22) translocation that fuses EWSR1 with the orphan nuclear receptor NR4A3, there are less common variants that partner NR4A3 with TAF15, TCF12, or TFG. By immunohistochemistry, EMC has features of both cartilaginous and neuroendocrine differentiation, as evidenced by inconsistent expression of S100 protein and synaptophysin or INSM1, respectively, in a subset of cases. Given the limitations of available immunohistochemical stains for the diagnosis of EMC, we analyzed genome-wide gene expression microarray data to identify candidate biomarkers based on differential expression in EMC in comparison with other mesenchymal neoplasms. This analysis pointed to CHRNA6 as the gene with the highest relative expression in EMC (96-fold; P = 8.2 × 10-26) and the only gene with >50-fold increased expression in EMC compared with other tumors. Using RNA chromogenic in situ hybridization, we observed strong and diffuse expression of CHRNA6 in 25 cases of EMC, including both EWSR1-rearranged and TAF15-rearranged variants. All examined cases of histologic mimics were negative for CHRNA6 overexpression; however, limited CHRNA6 expression, not reaching a threshold of >5 puncta or 1 aggregate of chromogen in >25% of cells, was observed in 69 of 685 mimics (10.1%), spanning an array of mesenchymal tumors. Taken together, these findings suggest that, with careful interpretation and the use of appropriate thresholds, CHRNA6 RNA chromogenic in situ hybridization is a potentially useful ancillary histologic tool for the diagnosis of EMC.

Comprehensive clinicopathological, molecular, and methylation analysis of mesenchymal tumors with NTRK and other kinase gene aberrations.

Alterations in kinase genes such as NTRK1/2/3, RET, and BRAF underlie infantile fibrosarcoma (IFS), the emerging entity 'NTRK-rearranged spindle cell neoplasms' included in the latest WHO classification, and a growing set of tumors with overlapping clinical and pathological features. In this study, we conducted a comprehensive clinicopathological and molecular analysis of 22 cases of IFS and other kinase gene-altered spindle cell neoplasms affecting both pediatric and adult patients. Follow-up periods for 16 patients ranged in length from 10 to 130 months (mean 38 months). Six patients were treated with targeted therapy, achieving a partial or complete response in five cases. Overall, three cases recurred and one metastasized. Eight patients were free of disease, five were alive with disease, and two patients died. All cases showed previously reported morphological patterns. Based on the cellularity and level of atypia, cases were divided into three morphological grade groups. S100 protein and CD34 were at least focally positive in 12/22 and 14/22 cases, respectively. Novel PWWP2A::RET, NUMA1::RET, ITSN1::RAF1, and CAPZA2::MET fusions, which we report herein in mesenchymal tumors for the first time, were detected by RNA sequencing. Additionally, the first uterine case with BRAF and EGFR mutations and CD34 and S100 co-expression is described. DNA sequencing performed in 13 cases uncovered very rare additional genetic aberrations. The CNV profiles showed that high-grade tumors demonstrate a significantly higher percentage of copy number gains and losses across the genome compared with low- and intermediate-grade tumors. Unsupervised clustering of the tumors' methylation profiles revealed that in 8/9 cases, the methylation profiles clustered with the IFS methylation class, irrespective of their clinicopathological or molecular features. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Pathogenic Somatic Mutation of DICER1 and Clinicopathological Features in Nasal Chondromesenchymal Hamartomas: A Series of Nine Cases.

Nasal chondromesenchymal hamartoma (NCMH) is a rare benign polypoid mesenchymal tumor arising in the nasal cavity and/or paranasal sinuses. Recognizing these sporadic, rare lesions is crucial, as surgical complete removal of the mass is the common treatment approach. This retrospective study analyzed the demographics, symptoms, and imaging data of 9 patients diagnosed with NCMH between January 2017 and June 2023, possibly representing the largest single-center adult case cohort to date. Diagnostic techniques included nasal endoscopy, CT/MRI scan, immunohistological studies, and morphologic comparisons. Pathologic specimens were subjected to Sanger sequencing of exons 24 and 25 of DICER1. The average age of 9 cases was 24.4 years, and the oldest was 55 years. Four of the patients were children, ranging from 1 year old to 11 years old, with an average of 4.5 years. Nasal congestion is the most common registered symptom. Endoscopic findings showed that most patients had smooth pink neoplasms or polypoid masses in the nasal meatus. Radiologic scanning revealed soft-tissue density masses that occupied the nasal cavity. Histologically, the characteristic structure of NCMHs is immature cellular cartilage nodules and mature cartilage nodules distributed in a loose mucoid matrix. Five of the 9 patients had somatic DICER1 missense mutations. Four of the patients with DICER1-mutated NCMH exhibited a p.E1813 missense hotspot mutation. We also report a case of a rare p.P1836H missense mutation. The detected DICER1 somatic mutations provide compelling evidence of an association with the DICER1 tumor family. We emphasize the importance of pathologic consultation and the need for pathologists to accumulate experience in NCMH diagnosis to avoid misdiagnosis.

Identification of Novel/Rare EWSR1 Fusion Partners in Undifferentiated Mesenchymal Neoplasms.

Recurrent gene fusions (GFs) in translocated sarcomas are recognized as major oncogenic drivers of the disease, as well as diagnostic markers whose identification is necessary for differential diagnosis. EWSR1 is a 'promiscuous' gene that can fuse with many different partner genes, defining different entities among a broad range of mesenchymal neoplasms. Molecular testing of EWSR1 translocation traditionally relies on FISH assays with break-apart probes, which are unable to identify the fusion partner. Therefore, other ancillary molecular diagnostic modalities are being increasingly adopted for accurate classification of these neoplasms. Herein, we report three cases with rare GFs involving EWSR1 in undifferentiated mesenchymal neoplasms with uncertain differential diagnoses, using targeted RNA-seq and confirming with RT-PCR and Sanger sequencing. Two GFs involved hormone nuclear receptors as 3' partners, NR4A2 and RORB, which have not been previously reported. NR4A2 may functionally replace NR4A3, the usual 3' partner in extraskeletal myxoid chondrosarcoma. The third GF, EWSR1::BEND2, has previously been reported in a subtype of astroblastoma and other rare entities, including a single case of a soft-tissue tumor that we discuss in this work. In conclusion, our findings indicate that the catalogue of mesenchymal neoplasm-bearing EWSR1 fusions continues to grow, underscoring the value of using molecular ancillary techniques with higher diagnostic abilities in the routine clinical setting.

Positron Emission Tomography/Computed Tomography Transformation of Oncology: Musculoskeletal Cancers.

The past 25 years have seen significant growth in the role of positron emission tomography/computed tomography (PET/CT) in musculoskeletal oncology. Substantiative advances in technical capability and image quality have been paralleled by increasingly widespread clinical adoption and implementation. It is now recognized that PET/CT is useful in diagnosis, staging, prognostication, response assessment, and surveillance of bone and soft tissue sarcomas, often providing critical information in addition to conventional imaging assessment. As individualized, precision medicine continues to evolve for patients with sarcoma, PET/CT is uniquely positioned to offer additional insight into the biology and management of these tumors.

18 F-FDG PET/CT Findings of Ovarian Myxoid Chondrosarcoma.

ABSTRACT: Ovarian myxoid chondrosarcoma is a rare and aggressive tumor. We present 18 F-FDG PET/CT findings of ovarian myxoid chondrosarcoma. The images not only demonstrated a pelvic mass with increased FDG uptake, but also a mass with increased FDG uptake in the right lower abdominal wall. Ovarian malignancy with abdominal wall metastases was suspected. An extraskeletal myxoid chondrosarcoma was diagnosed histopathologically after the mass excision.

Superficial CD34-Positive Fibroblastic Tumor.

Superficial CD34-positive fibroblastic tumor is a mesenchymal neoplasm of "intermediate malignancy" recently included in the fifth edition of the World Health Organization classification of soft tissue and bone tumors. In this review, we summarize the current knowledge on this rare entity with a special focus on its clinicopathological features, morphologic spectrum, and differential diagnosis. We also provide data regarding recent discoveries on its molecular profile and discuss its prognosis and management.

Soft Tissue Perivascular Epithelioid Cell Tumors.

Perivascular epithelioid cell tumors (PEComas) are a heterogenous group of mesenchymal neoplasms with a mixed myomelanocytic immunophenotype. PEComa-family tumors include angiomyolipoma, lymphangioleiomyomatosis, and a large category of rare neoplasms throughout the body that are now classified under the umbrella term "PEComa." This review focuses on recent advances in the clinicopathological and molecular features of PEComas, with an emphasis on PEComas that originate in soft tissue.

Uterine Sarcoma With EML4::NTRK3 Fusion: A Spectrum of Mesenchymal Neoplasms Harboring Actionable Gene Fusions.

NTRK gene fusions are part of a paradigm shift in oncology, arising as one of the main genomic alterations with actionability in the so-called "agnostic setting." In gynecologic pathology, the recent description of uterine sarcoma resembling fibrosarcoma and with NTRK rearrangements ( NTRK -rearranged uterine sarcoma) highlights the importance of recognizing clinicopathological cues that can lead to genomic profiling. Herein, we report the case of a 43-year-old woman presenting with vaginal bleeding and pelvic mass. Histopathology of the tumor showed moderately atypical spindle cells arranged in long fascicles reminiscent of fibrosarcoma, along with immunohistochemical positivity for S100, CD34, and pan-tropomyosin receptor kinase. This prompted RNA-sequencing and the finding of a rare EML4::NTRK3 fusion. Clinical, histologic, and molecular findings are described, in addition to discussions regarding differential diagnoses and possible implications of the findings in clinical practice.

Prevalência de lesões bucais em tecidos mole e duro diagnosticadas em idosos em um serviço histopatológico de referência / Prevalence of oral lesions in soft and hard tissue in elderly patients in a single histopathological service / Prevalencia de lesiones bucales en tejido blando y duro enancianos diagnosticadas en un servicio de referencia histopatológico

O envelhecimento populacional é um fenômeno mundial, sendo percebido também no estado do Amazonas. Com a alta expectativa de vida, o enfoque na saúde geral e bucal impactam diretamente a qualidade de vida da pessoa. Desta forma, os levantamentos acerca da população geriátrica não devem ser restritos às alterações fisiológicas da idade, devendo abordar também as manifestações patológicas, retratando assim quais são as lesões bucais mais recorrentes. O trabalho em questão visa levantar o número de lesões bucais prevalentes em tecido mole e duro em idosos. Sendo feito a partir de um levantamento das lesões bucais prevalentes em tecido mole e duro que acometeram os idosos registrados nos laudos do Serviço de Patologia Oral e Maxilofacial da Universidade do Estado do Amazonas, SEPAT-UEA, entre os anos de 2012 a 2018. Segundo os dados coletados, a categoria de neoplasias de tecido mole (28,94%) teve o maior número de casos, em que a lesão mais prevalente, sendo esta do mesmo grupo, foi a hiperplasia fibrosa inflamatória (14,04%). Teve maior acometimento em mulheres (54,91%), pessoas com 60-69 anos (74,77%), usuários de próteses removíveis (15,56%) e a mandíbula (17,28%) foi a localização mais comum. Com as informações adquiridas, a partir de um serviço de referência do estado do Amazonas, é possível ter um melhor direcionamento dos recursos para a população geriátrica tendo um maior enfoque para as lesões mais prevalentes visando assim uma melhor saúde bucal e consequentemente uma melhor qualidade de vida(AU)

Population aging is a worldwide phenomenon, and is also noticed in the state of Amazonas. According to the high life expectancy, the focus on general health and the oral impact directly on the person's quality of life. Thus, surveys about thegeriatric population should not be restricted as physiological changes in age, but should also be addressed as pathological manifestations, thus portraying which are the most recurrent oral lesions. The aim of the study is to raise the frequency of the most prevalent of oral lesions in soft and hard tissue in the elderly. Being made from a survey of oral lesions in soft and hard tissue that affected the elderly registered in the reports of the Oral and Maxillofacial Pathology Service of the Amazonas State University, SEPAT-UEA, between the years 2012 to 2018. According to collected data, the category of soft tissue neoplasms (28.94%) had the highest number of cases, in which the most prevalent lesion, being the same group, for an inflammatory fibrous hyperplasia (14.04%). It was more recurrent in women (54.91%), elderly in 60-69 years (74.77%), users of removable prosthesis (15.56%) and the mandible (17.28%) was the most common location. With the information acquired, from a reference service in the state of Amazonas, it is possible to have a better targeting of resources for the geriatric population, with agreater focus on the most prevalent injuries, thus better oral health and consequently a better quality of life care(AU)

El envejecimiento de la población es un fenómeno mundial, se percibe también en el estado de Amazonas. Con la alta expectativa de vida, el enfoque en la salud general y bucal impactan directamente la calidad de vida de la persona. De esta forma, las encuestas sobre la población geriátrica no deben restringir a los cambios fisiológicos de la edad, sino que deben abordar también las manifestaciones patológicas, describiendo así cuáles son las lesiones bucales más recurrentes. El trabajo en cuestión tiene por objeto levantar el número de lesiones bucales prevalentes en tejido blando y duro en ancianos. Se realiza a partir de um estudio de las lesiones bucales prevalentes que han afectado a los ancianos registrados en los informes del Servicio de Patología Oral y Maxilofacial de la Universidad del Estado de Amazonas, SEPAT-UEA, entre los años 2012 a 2018. Según los datos recogidos, la categoría de neoplasias de tejidos blandos (28,94%) presentó el mayor número de casos, en la que la lesión más prevalente fue la hiperplasia fibrosa inflamatoria (14,04%). Fue más afectado por mujeres (54,91%), personas de 60 a 69 años (74,77%), usuarios de prótesis removibles (15,56%) y la mandíbula (17,28%) fue la localización más común. Con la información adquirida, de un servicio de referencia en el estado de Amazonas, es posible tener una mejor focalización de recursos para la población geriátrica, con un mayor enfoque en las lesiones más prevalentes, apuntando así a una mejor salud bucal y consecuentemente una mejor calidad de vida(AU)

Úlcera de Marjolin: 2 casos de carcinoma escamoso sobre cicatriz por trauma en tejidos blandos / Marjolin Ulcer: A Report of 2 Cases of Squamous Cell Carcinoma Arising From Posttraumatic Soft-Tissue Scarring

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Myopericytoma of the tongue base: A case report / Miopericitoma de la base lingual: presentación de un caso clínico

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Evaluation of adjuvant chemotherapy in feline injection site-associated sarcoma / Avaliação da quimioterapia no tratamento do sarcoma de aplicação felino

Feline Injection Site-Associated Sarcoma (FISS) is a neoplasm that implies in reduction of quality of life and overall survival in feline patients. A retrospective study of 13 cases of FISS was conducted to evaluate the efficacy of surgical treatment associated to chemotherapy with doxorubicin or carboplatin. Local recurrence occurred in all patients. Patients treated with surgery and chemotherapy presented a longer overall survival and disease-free interval when compared to those that solely received surgical treatment, although no statistical significance was observed (p= 0.3360 and 0.7506, respectively). Surgery remains as the main option for FISS treatment. Further prospective studies with larger samples are warranted to investigate the benefit of chemotherapy for this neoplasm.(AU)

O Sarcoma de Aplicação Felino (SAF) é uma neoplasia associada a redução na qualidade de vida e sobrevida global. O objetivo deste estudo foi avaliar a eficácia da quimioterapia associada à cirurgia no manejo do SAF. Estudo retrospectivo de 13 pacientes com SAF submetidos à cirurgia isolada ou associada a quimioterapia com carboplatina ou doxorrubicina. Recorrência local ocorreu em todos os pacientes. Pacientes tratados com cirurgia e quimioterapia apresentaram maior sobrevida global e intervalo livre de doença quando comparados àqueles que receberam apenas tratamento cirúrgico, mas não foi observada diferença estatística (p=0,3360 e 0,7506, respectivamente). A cirurgia continua sendo a principal opção para o tratamento do SAF. Estudos prospectivos são necessários para investigação do real benefício da quimioterapia para esta neoplasia.(AU)

Liquid-based cytology diagnosis of endoscopic ultrasound-guided fine needle aspiration of pancreatic lesions / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the diagnostic value of liquid-based cytology test (LCT) in pancreatic lesions sampled by ultrasound-guided fine needle aspiration (EUS-FNA).</p><p><b>METHODS</b>A retrospective analysis of 556 cases of LCT smears sampled by EUS-FNA of pancreatic lesions was performed, and 164 cases had histologic diagnosis with subsequent surgical resection or biopsy and immunohistochemistry. The accuracy of the cytologic diagnosis was assessed using the histologic diagnosis as the gold standard. The discrepant cases were reviewed to identify sources of errors.</p><p><b>RESULTS</b>The satisfactory rate for EUS-FNA was 96.0%(534/556). The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy were 87.7%(128/146), 13/16, 97.7%(128/131), 41.9%(13/31) and 87.0%(141/162) respectively. The diagnostic accuracy was lower in cystic lesions than that in solid lesions. The LCT sensitivities of adenocarcinoma, lymphoma and neuroendocrine tumors were higher than those of cystic tumors and mesenchymal tumors. False positive diagnosis was mainly due to epithelial abnormalities in inflammatory reaction. False negative diagnosis was mainly due to scanty or lack of tumor cells in the smears, or mild atypia that was insufficient for diagnosis.</p><p><b>CONCLUSIONS</b>EUS-FNA is a valuable tool for the diagnosis of pancreatic lesions. Standardized terminology and nomenclature are helpful to improve the diagnostic accuracy.</p>

Extraskeletal myxoid chondrosarcoma: a clinicopathologic analysis of seven cases / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the clinicopathologic features, diagnosis and differential diagnosis of extraskeletal myxoid chondrosarcoma (EMC).</p><p><b>METHODS</b>The clinical and pathologic features of 7 cases of EMC encountered in Fujian Provincal Hospital and Fuzhou General Hospital of Nanjing Military Command during the period of 2005 to 2015 were analyzed. Immunohistochemical study and PAS staining were carried out. Relevant literature was reviewed.</p><p><b>RESULTS</b>The male-to-female ratio was 6 to 1. The age of patients ranged from 21 to 50 years (median = 36 years). The maximum tumor dimension ranged from 2.5 to 15.0 cm (mean = 8.4 cm). The sites of involvement included left neck, right shoulder, left thigh, right thigh, right upper arm and abdomen. Most patients presented with painless lumps. Histologically, all cases showed similar features. Low-power examination showed a nodular or lobulated architecture, with intervening fibrous septa and myxoid matrix in the background. The tumor cells were arranged in cords or tufted clusters. They were spindly to epithelioid / rhabdoid (plasmacytoid) in shape, with eosinophilic to sometimes vacuolated cytoplasm. Intracytoplasmic eosinophilic inclusion bodies and coagulative necrosis were focally seen. Mitotic figures were rare (less than 2 per 10 high-power fields). Immunohistochemical study showed that the tumor cells were positive for vimentin (7/7) and INI1 (7/7). They were focally positive for CKpan (2/7), p63 (3/7), CD99 (3/7), S-100 protein (1/7) and synaptophysin (2/7). Ki-67 proliferation index ranged from 10% to 40%. The tumor cells were negative for α-smooth muscle actin, desmin, myoD1, CD34 and CD117. The cytoplasm of the tumor cells was positive for PAS. EWSR1 gene signal was detected in 5 cases.</p><p><b>CONCLUSIONS</b>EMC is a rare malignant mesenchymal tumor. Arrival at correct diagnosis relies on morphologic examination and immunohistochemistry. Molecular pathology is helpful when necessary. The primary treatment modality for EMC is complete surgical excision and the prognosis is satisfactory.</p>