Proximal-type epithelioid sarcoma: a clinicopathologic study of 20 cases

Neck Epithelioid Sarcoma at an Unusual Location Mimicking Lymph Node Metastases of Nasopharyngeal Carcinoma: A Case Report

Epithelioid sarcoma (ES) is an uncommon soft tissue sarcoma. It is usually located in the extremities and exceptionally in the neck. Its diagnosis constitutes a real challenge which is based on histology and immunohistochemistry staining that must be interpreted with caution given the anatomopathological similarities to other tumors. In this article, we report a case of a 37-year-old man admitted for a locally advanced ES of the neck. There were suspicions of lymph node metastases of nasopharyngeal carcinoma at the first pathological examination. The patient received palliative chemotherapy and was referred to the supportive care department. Through this case, we will discuss the clinical and anatomopathological characteristics and therapeutic options of this extremely rare tumor which poses a diagnostic challenge.

The over diagnosis of diffuse mesothelioma: An analysis of 311 cases with recommendations for the avoidance of pitfalls

BACKGROUND

The diagnosis of mesothelioma may be challenging. We investigated a large database of cases in order to determine the frequency with which a diagnosis of mesothelioma was made incorrectly and the most frequent causes of error.

DESIGN

A database including more than 4000 consultation cases of histologically confirmed mesothelioma was examined to identify cases in which mesothelioma was diagnosed by at least one pathologist when the available information pointed towards a different diagnosis.

RESULTS

There were 311 cases misdiagnosed as mesothelioma. The most common category was metastatic carcinoma to the pleura or peritoneum (129 cases: 73 lung carcinomas, 15 renal cell carcinomas). The next most common category was primary lung cancer (111 cases: 55 sarcomatoid carcinoma, 56 pseudomesotheliomatous carcinoma). The third most common category was primary malignancies arising from or near the serosal membranes (33 cases). The fourth most common category was fibrous pleurisy (38 cases). The most common errors were failure to consider important radiographic information regarding the gross distribution of tumor, lack of awareness or consideration of another malignancy, overreliance on certain immunohistochemical results, and failure to perform certain diagnostic histochemical, immunohistochemical, or ultrastructural studies.

CONCLUSIONS

There are a number of diagnostic pitfalls that can lead to the over diagnosis of mesothelioma. Careful attention to clinical and radiographic information as well as performance of appropriate ancillary tests can help to prevent such misdiagnoses. Detailed examples will be presented to assist in the avoidance of these pitfalls with emphasis on the most commonly observed errors.

Angiosarcoma of gallbladder, a literature review

BACKGROUND

Angiosarcoma of the gallbladder is a rare diagnostic entity rarely encountered by pathologists and has rarely been reported in literature. This review aimed to examine the clinicopathological features, immunohistochemistry, treatment, and outcomes of gallbladder angiosarcoma.

METHODS

A search of the PubMed, Science Direct and Google Scholar was done with the search terms ("angiosarcoma" OR "angiosarcomas") AND ("gallbladder" OR "gallbladders"). Based on inclusion and exclusion criteria, only case reports could be used for this review.

RESULT

8 case reports were chosen in the end for analysis. The mean age of the patients at presentation was 65 years. It was most frequently observed in males. Abdominal pain and palpable mass were the most commonly reported symptoms. Cholelithiasis and anemia were also reported. On histopathology morphologically epithelioid appearance of angiosarcoma was evident. Cytokeratin (CK) AE1/AE3, Von willebrand factor, Factor VIII antigen, Vimentin, CD31 were positive. Meanwhile, UEA, CD34, CD117, S-100, Keratin, EMA, and CEA showed negative outcome. Surgery was the preferred method of treatment and a mean 10-months follow-up was done.

CONCLUSION

Despite the unavailability of convincing data, histological and immunohistochemical analyses play a major role in the diagnosis of gallbladder angiosarcoma. Nevertheless, more comprehensive clinical studies are required to provide universal guidelines for the treatment and diagnosis of angiosarcoma of the gallbladder.

Subclassification of epithelioid sarcoma with potential therapeutic impact

Epithelioid sarcoma is a rare and aggressive mesenchymal tumour, the genetic hallmark of which is the loss of expression of SMARCB1, a key member of the SWItch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodelling complex. Hampered by its rarity, epithelioid sarcoma has received little research attention and therapeutic options for this disease remain limited. SMARCB1-deficient tumours also include malignant rhabdoid tumour, atypical teratoid and rhabdoid tumour, epithelioid malignant peripheral nerve sheath tumour, and poorly differentiated chordoma. Histologically, it can be challenging to distinguish epithelioid sarcoma from malignant rhabdoid tumour and other SMARCB1-deficient tumours, whereas methylation profiling shows that they represent distinct entities and facilitates their classification. Methylation studies on SMARCB1-deficient tumours, although not including epithelioid sarcomas, reported methylation subgroups which resulted in new clinical stratification and therapeutic approaches. In addition, emerging evidence indicates that immunotherapy, including immune checkpoint inhibitors, represents a promising therapeutic strategy for SMARCB1-deficient tumours. Here, we show that some epithelioid sarcomas share methylation patterns of malignant rhabdoid tumours indicating that this could help to distinguish these entities and guide treatment. Using gene expression data, we also showed that the immune environment of epithelioid sarcoma is characterised by a predominance of CD8+ lymphocytes and M2 macrophages. These findings have potential implications for the management of patients with epithelioid sarcoma. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

A multi-disciplinary team approach to pediatric malignant mandibular tumors

OBJECTIVE

Mandibular tumors in the pediatric population are rare. These malignancies are variable in their histology, and combined with their rarity, has made it difficult to describe their clinical course, and treatment guidelines. The aim of this paper is to describe the experience of Boston Children's Hospital, a pediatric tertiary referral center, with treating malignant mandibular malignancies, as well as provide multi-disciplinary team approach in managing this clinical entity.

METHODS

A retrospective search was performed for mandibular malignancies in pediatric patients between 1995 and 2020 via the pathological database at Boston Children's Hospital. Only patients with malignant solid mandibular neoplasms were included, leaving 15 patients for final analysis.

RESULTS

The median age at presentation was 10.1 ± 10.3 years. Nine of 15 patients (60%) presented with jaw mass which was the most common clinical presentation. The most commonly identified histological diagnosis was rhabdomayosarcoma and osteosarcoma (n = 4, 26% each). A mandibulectomy was performed in 12 (80%) cases. Reconstruction of the mandible was performed using a fibular free flap in 6 (40%) cases, and a plate in 3 (20%) cases. Mean follow-up was 4.6 ± 4.9 years.

CONCLUSION

Malignant tumors most commonly present with a jaw mass, however asymptomatic and incidental presentations follow closely and pathologies can vary greatly. Surgical resection and reconstruction is often indicated, multidisciplinary tumor board review is required to determine when children are best treated with neo-/adjuvant treatment with chemo- and radiotherapy.

Proximal-type epithelioid sarcoma of the perineum: A case report and literature review

Proximal-type epithelioid sarcoma of the perineum is a rare soft-tissue malignancy, and only 55 cases have been reported in the English literature to date. This tumor has an indetectable early symptom and frequent recurrences. Here, we present the case of a 31-year-old man with proximal-type epithelioid sarcoma of the perineum who underwent wide excision. Further, we reviewed the current literature regarding differential diagnosis and management of this disease.

Clinicopathological Characteristics, Treatment, and Survival in Patients Diagnosed With Proximal-Type Epithelioid Sarcoma: A Case Report and Systematic Review

Epithelioid sarcoma is a rare entity that shows a predilection for the young and middle-aged population. There are two subtypes, i.e., the distal or conventional type, which is located in distal extremities, and the proximal type, located in proximal areas of the extremities, pelvis, perineal, and genital region. The latter is characterized by more aggressive behavior, a higher recurrence rate, and poor prognosis. Histopathological and immunohistochemical diagnoses are key to correct and timely treatment and a higher survival rate. We report a case of a 41-year-old man who presented a palpable progressive growth mass in the hypogastrium. The disease time was of nine months, and the tumor was resected, but it recurred a few months later in the same location. Computed tomography (CT) scans showed images suggestive of lung metastasis and the patient had to undergo a second surgery. He received eight cycles of chemotherapy and a subsequent CT scan control showed the progression of the disease, so a new chemotherapy regimen was established. The patient received three cycles of chemotherapy without improvement, so he decided to discontinue treatment. His last outpatient medical consultation was in January 2022. A systematic review of the studies published in PubMed and Google Scholar was performed. We identified 291 articles, but only 41 reports and case series were included, with a total of 55 patients. It is important to include this type of tumor in the differential diagnosis of epithelial tumors due to its aggressive behavior. Correct and timely diagnosis is crucial to obtain lower recurrence rates, lower mortality, and higher survival rates in these patients.

Beyond SMARCB1 Loss: Recent Insights into the Pathobiology of Epithelioid Sarcoma

Epithelioid sarcoma (ES) is a very rare and aggressive mesenchymal tumor of unclear origin and uncertain lineage characterized by a prevalent epithelioid morphology. The only recurrent genetic alteration reported in ES as yet is the functional inactivation of SMARCB1 (SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily B member 1), a key component of the SWI/SNF (SWItch/Sucrose Non-Fermentable) chromatin remodeling complexes. How SMARCB1 deficiency dictates the clinicopathological characteristics of ES and what other molecular defects concur to its malignant progression is still poorly understood. This review summarizes the recent findings about ES pathobiology, including defects in chromatin remodeling and other signaling pathways and their role as therapeutic vulnerabilities.

Epithelioid leiomyosarcoma of the vulva: report of a rare case and literature review

Leiomyosarcoma of the vulva is a rare soft tissue sarcoma that accounts for approximately 1% of all primary vulvar neoplasms, but it is the most common type of vulvar sarcoma. It usually originates from the smooth muscle within erectile tissue or blood vessel walls, the round ligament, the dartos muscle or the arrector pili muscle. No treatment algorithms have been established to date. Surgical resection is preferred for vulvar leiomyosarcoma. Currently, the recommended surgical method is extensive local resection with a safe surgical margin of at least 2 cm. The use of chemoradiotherapy for vulvar sarcoma remains controversial. This case report describes a 39-year-old female that underwent resection of a vulvar mass in January 2019. Postoperative pathological examination indicated that it was an epithelioid leiomyosarcoma. She presented with tumour recurrence after 43 days. Based on the diagnosis, radical right vulvectomy with a tumour margin of 2 cm was performed. The tumour margin was negative. The patient refused to undergo auxiliary radiotherapy and chemotherapy. The follow-up findings do not indicate any signs of recurrence. In order to avoid recurrence, vulvar epithelioid leiomyosarcomas should be completely resected with a margin of 2 cm at the time of first occurrence.

Primary Adrenal Epithelioid Sarcoma in a Child: A Case Report with Literature Review

Introduction; Epithelioid sarcoma is a malignant mesenchymal neoplasm with evidence of epithelial differentiation. All the cases reported in the solid organs are of "proximal type" occurring in adults. We report a primary epithelioid sarcoma arising in the adrenal gland of a young male. Case report: An 11-year-old male patient presented with right loin pain. Imaging revealed a 10.8 × 10.8 × 13.5 cm complex cystic mass with obscured right adrenal gland. Clinical and radiological studies did not reveal metastases. Histologic features were those of proximal type epithelioid sarcoma with extensive central necrosis. Immunohistochemistry showed strong positivity for pancytokeratin, vimentin, and CD34. Nuclear expression of SMARCB1 (INI-1) protein was lost. Conclusion: Proximal type of epithelioid sarcoma can arise from solid organs such as the adrenal.

Proximal-type epithelioid sarcoma in pubic region expressing L-type amino acid transporter 1: A case report

Proximal-type epithelioid sarcoma is an aggressive malignant soft-tissue neoplasm, a “proximal” variant of epithelioid sarcoma, resistant to multimodal therapy and involved in early tumor-related death. Pertinent treatments are, therefore, continually being explored. A 24-year-old woman with nonmetastatic proximal-type epithelioid sarcoma, originating subcutaneously on the right side of the vulva, underwent surgical resection; the lesion recurred, however, leading to death 3 months after the second surgery. Here described is a case of proximal-type epithelioid sarcoma expressing L-type amino acid transporter 1 (LAT1) that transports essential amino acids and p-borono-L-phenylalanine (BPA)—the chemical compound used in boron neutron capture therapy (BNCT)—and is highly expressed in many malignant tumors. Recently, LAT1 has drawn attention, and relevant treatments have been studied—LAT1 inhibitor and BNCT. LAT1 expression in proximal-type epithelioid sarcoma may lead to cogent treatments for the disease.

The 2021 World Health Organization Classification of Tumors of the Pleura: Advances since the 2015 Classification

Significant changes in the 2021 World Health Organization (WHO) Classification of Tumors of the Pleura and Pericardium since the 2015 WHO Classification include: 1) Pleural and pericardial tumors have been combined in one chapter whereas in the 2015 WHO, pericardial tumors were classified with cardiac tumors; 2) Well-differentiated papillary mesothelioma (WDPM) has been renamed well-differentiated papillary mesothelial tumor (WDPMT) given growing evidence that these tumors exhibit relatively indolent behavior; 3) Localized and diffuse mesothelioma no longer include the term "malignant" as a prefix; 4) Mesothelioma in situ (MIS) has been added to the 2021 classification since these lesions can now be recognized by loss of BAP1 and/or MTAP by immunohistochemistry and/or CDKN2A homozygous deletion by FISH; 5) The three main histologic subtypes (i.e. epithelioid, biphasic and sarcomatoid) remain the same but architectural patterns, cytologic and stromal features are more formally incorporated into the 2021 classification based on their prognostic significance; 6) Nuclear grading for epithelioid diffuse mesothelioma is introduced and it is recommended to record this and other histologically prognostic features in pathology reports; 7) BAP1, EZH2 and MTAP immunohistochemistry have been shown to be useful in separating benign mesothelial proliferations from mesothelioma; 8) Biphasic mesothelioma can be diagnosed in small biopsies showing both epithelioid and sarcomatoid components even if the amount of one component is less than 10%; and 9) The most frequently altered genes in diffuse pleural mesothelioma include BAP 1, CDKN2A, NF2, TP53, SETD2 and SETB1.

Primary adult sellar SMARCB1/INI1-deficient tumor represents a subtype of atypical teratoid/rhabdoid tumor

Loss of function in SMARCB1/INI1 has been observed in a group of malignancies collectively defined as SMARCB1/INI1-deficient neoplasms. Primary intracranial SMARCB1/INI1-deficient tumors in adults are extremely rare. We collected eight primary adult sellar SMARCB1/INI1-deficient tumors to study their clinicopathological and (epi)genetic characteristics. We performed a comprehensive assessment of the clinical, radiological, morphological and immunohistochemical features. FISH analysis for the SMARCB1 locus and target exome sequencing for 425 cancer relevant genes were performed. Furthermore, six bona fide proximal epithelioid sarcoma (PES), fourteen atypical teratoid/rhabdoid tumors (ATRT) in brain and five pediatric poorly differentiated chordomas (PDC) in the clivus were collected for comparative analysis of differential diagnostic maker expression and DNA methylation profile. The median age was 47.1 years, ranging from 26 to 73 years. On morphology, tumors were characterized by sheets of monomorphic larger epithelioid-like cells, in two cases with rhabdoid cells. "Stag-horn" vasculatures were observed in five cases. The loss of INI1 protein expression, co-expression of epithelial makers and mesenchymal markers were observed in all cases. CD34 expression was observed in six cases. Heterozygous deletion of SMARCB1/INI1 was confirmed using FISH in six cases. The results of target exome sequencing showed three patients harbored heterozygous point mutations in SMARCB1. The epigenetic features of the primary adult sellar SMARCB1/INI1-deficient tumors resembled the ATRT-MYC subgroup, but clustered apart from PES and PDC. Based on epigenetic characteristics, primary adult sellar SMARCB1/INI1-deficient tumors represent a subtype of ATRT with similar epigenetic characteristics of ATRT-MYC subgroup. Our findings suggest that DNA methylation profiling should be utilized for differential diagnosis for the majority of epithelioid sarcoma and (sellar) rhabdoid tumor.

CHIR99021, trough GSK-3β Targeting, Reduces Epithelioid Sarcoma Cell Proliferation by Activating Mitotic Catastrophe and Autophagy

Epithelioid sarcoma (ES) is a rare disease representing <1% of soft tissue sarcomas. Current therapies are based on anthracycline alone or in combination with ifosfamide or other cytotoxic drugs. ES is still characterized by a poor prognosis with high rates of recurrence. Indeed, for years, ES survival rates have remained stagnant, suggesting that conventional treatments should be revised and improved. New therapeutic approaches are focused to target the key regulators of signaling pathways, the causative markers of tumor pathophysiology. To this end, we selected, among the drugs to which an ES cell line is highly sensitive, those that target signaling pathways known to be dysregulated in ES. In particular, we found a key role for GSK-3β, which results in up-regulation in tumor versus normal tissue samples and associated to poor prognosis in sarcoma patients. Following this evidence, we evaluated CHIR99021, a GSK-3 inhibitor, as a potential drug for use in ES therapy. Our data highlight that, in ES cells, CHIR99021 induces cell cycle arrest, mitotic catastrophe (MC) and autophagic response, resulting in reduced cell proliferation. Our results support the potential efficacy of CHIR99021 in ES treatment and encourage further preclinical and clinical studies.

Vulvar epithelioid sarcoma: A case report with literature review

OBJECTIVE

To report a case of vulvar epithelioid sarcoma, a rare type of tumor that has been reported in 37 cases in the English literature to date.

CASE REPORT

We report three cases of vulvar epithelioid sarcoma, proximal type. Wide excisions of the mass were performed with margins free of tumor in all three cases.

CONCLUSION

Due to its low incidence, there are no evidence-based diagnostic algorithms or published recommendations for treatment. Locoregional lymph node involvement, vascular invasion, tumor size larger than 2 cm, deep localization, presence of necrosis, and a high mitotic index are known as poor prognostic factors. Adjuvant radiotherapy is advisable in the presence of a high-grade tumor or positive margins. The beneficial effect of adjuvant chemotherapy is not well established. Treatment decisions should be made based on the individual case presentation and pathology evaluation.

Mesenchymal/non-epithelial mimickers of neuroendocrine neoplasms with a focus on fusion gene-associated and SWI/SNF-deficient tumors

Mimickers of neuroendocrine neoplasms (NEN) include a number of important pitfall tumors. Here, we describe our experience with mesenchymal mimics of NENs to illustrate their spectrum and draw the attention particularly to a group of mesenchymal/non-epithelial neoplasms (MN) that combine epithelioid histology with neuroendocrine (NE-) features and peculiar genetic abnormalities. In a consultation series of 4498 cases collected between 2009 and 2021, 2099 neoplasms expressing synaptophysin and/or chromograninA were reviewed and analyzed. A total of 364 (18%) were diagnosed as non-NENs, while the remaining tumors were NEN. The group of mesenchymal/non-epithelial neoplasms with NE-features (MN-NE) included 31/364 (8%) cases. These mostly malignant neoplasms showed an epithelioid morphology. While all but one tumor expressed synaptophysin, mostly patchy, only 10/29 (34%) co-expressed chromograninA. A total of 13/31 (42%) of the MN-NE showed EWSR1-related gene fusions (6 Ewing sarcomas, 5 clear cell sarcomas, and 1 desmoplastic small round cell tumor, 1 neoplasm with FUS-CREM gene fusion) and 7 (23%) were SWI/SNF (SMARCB1 or SMARCA4)-deficient neoplasms. The remaining MN-NE included synovial sarcoma, sclerosing epithelioid mesenchymal neoplasm, melanoma, alveolar soft part sarcoma, solitary fibrous tumor, and chordoma. A total of 27/31 MN-NE were from the last 8 years, and 6 of them were located in the pancreas. Eleven MN-NE were initially diagnosed as neuroendocrine carcinomas (NECs). MN-NE with epithelioid features play an increasing role as mimickers of NECs. They mostly belong to tumors with gene fusions involving the EWSR1 gene, or with SWI/SNF complex deficiency. Synaptophysin expression is mostly patchy and chromograninA expression is infrequent in MN-NE of this series and data extracted from literature.

Epithelioid sarcoma of the parapharyngeal space: A case report

Epithelioid sarcoma (ES) was first described by Enzinger in 1970. It is a rare variant of soft tissue sarcoma with a 5-year overall survival (OS) rate of 50%. Here, we reported a case of epithelioid sarcoma in the parapharyngeal space of an adult, resulting in a favorable prognosis after chemotherapy and radiation therapy. A 34-year-old female who complained of pharynx pain and discomfort was suspected of having a tumor in the right parapharyngeal space by CT scan. Excision biopsy suggested epithelioid sarcoma. Clinical and radiological studies did not reveal tumor distant metastasis in the patient. After excisional biopsy, the patient underwent chemotherapy and external beam radiation treatment. She has remained alive for 2 years and 7 months without recurrence since her last treatment. In this paper, we also provide a detailed review of the role of radiotherapy in the treatment of epithelioid sarcoma in previously reported cases.

Myxoepithelioid tumour with chordoid features: a clinicopathological, immunohistochemical and genetic study of 14 cases of SMARCB1/INI1-deficient soft-tissue neoplasm

AIMS

Complete loss of SMARCB1/INI1 in soft-tissue tumours such as malignant rhabdoid tumour, epithelioid sarcoma, myoepithelial tumour of soft tissue and extraskeletal myxoid chondrosarcoma is often associated with high-grade malignancy and poor prognosis. The diagnosis is sometimes challenging, owing to histological similarities, so careful differential diagnosis is required. Therefore, soft-tissue tumours with complete SMARCB1/INI1 loss could potentially include an unknown entity.

METHODS AND RESULTS

We analysed 160 cases of SMARCB1/INI1-deficient soft-tissue tumour, and found 14 cases that were not classifiable into already existing categories and had common clinical and histological features. These involved two male and 12 female patients, ranging in age from 20 years to 61 years. The tumours were located in the the puboinguinal region (n = 13) and pelvic cavity (n = 1). Histologically, the tumours showed relatively uniform epithelioid to spindle-shaped cells with myxoid stroma. All tumours showed immunoreactivity for brachyury, epithelial membrane antigen, and progesterone receptor, and 12 of 14 cases did so for oestrogen receptor. Variable positive staining for α-smooth muscle actin, S100 and glial fibrillary acidic protein (GFAP) was seen. NR4A3 and EWSR1 gene rearrangements were not detected in 13 and 11 examined cases, respectively. Clinical follow-up data for the 14 patients showed that 13 were alive without disease and one had been lost to follow-up; four patients developed local recurrence and/or metastases.

CONCLUSION

The designation 'myxoepithelioid tumour with choroid features' (METC) was proposed as a tumour with intermediate malignancy controllable with appropriate treatment, including the entity of myoepithelioma-like tumour of the vulvar region. METC represents a novel and independent subset that is histologically, biologically and clinically distinct from already existing SMARCB1/INI1-deficient soft-tissue tumours.

SMARCB1/INI1-deficient tumors of adulthood

The SMARCB1/INI1 gene was first discovered in the mid-1990s, and since then it has been revealed that loss of function mutations in this gene result in aggressive rhabdoid tumors. Recently, the term "rhabdoid tumor" has become synonymous with decreased SMARCB1/INI1 expression. When genetic aberrations in the SMARCB1/INI1 gene occur, the result can cause complete loss of expression, decreased expression, and mosaic expression. Although SMARCB1/INI1-deficient tumors are predominantly sarcomas, this is a diverse group of tumors with mixed phenotypes, which can often make the diagnosis challenging. Prognosis for these aggressive tumors is often poor. Moreover, refractory and relapsing progressive disease is common. As a result, accurate and timely diagnosis is imperative. Despite the SMARCB1/INI1 gene itself and its implications in tumorigenesis being discovered over two decades ago, there is a paucity of rhabdoid tumor cases reported in the literature that detail SMARCB1/INI1 expression. Much work remains if we hope to provide additional therapeutic strategies for patients with aggressive SMARCB1/INI1-deficient tumors.

An Extremely Rare Epithelioid Sarcoma Arising from the Infratemporal Fossa: A Case Report and Literature Review

INTRODUCTION

Epithelioid sarcoma (ES) is a rare histopathological type of soft tissue sarcoma. They are subcutaneous soft tissue masses that tend to arise in extremity sites (the classic type, formerly referred to as distal type) or proximal midline region of the body (the proximal type), such as the perineum, genital tract, and pelvis. The head and neck regions are rarely affected by ES, but the infratemporal fossa (ITF) is extremely rare. ES involving the ITF has not been reported before in literature. In this paper, the imaging features of ES were reviewed in detail, and the anatomical structure and epidemiology of ITF were briefly introduced.

SOURCES

We performed a systematic search from 3 databases, CNKI(China National Knowledge Internet), FMRS(Foreign Medical Literature Retrieval Service, Shenzhen METSTR Technology CO., Led. China), and PubMed, to obtain literature from January 1970 to July 2020. Epithelioid sarcoma, head and neck regions, infratemporal fossa, diagnostic imaging, anatomy, MRI, and CT were used as keywords for advanced retrieval. A study had to be found eligible for inclusion to be closely related to ES and/or ITF. A total of 129 related pieces of literature were retrieved successfully, of which 37 were closely related to this study. The case report in this article is from the Affiliated Hospital of North Sichuan Medical College. The present study was approved by the institutional review board of the Affiliated Hospital of North Sichuan Medical College and a written informed consent for the publication of the case was obtained from the patient.

CASE PRESENTATION

A 33-year-old man accidentally found a slowly growing, painless mass in the left cheek more than a month ago. On plain computed tomography (CT) scan of the outpatient department, an oval slightly low-density mass with well-defined and uniform boundary in the infratemporal fossa was revealed, and on the contrast-enhanced scan, it was homogeneous and moderately enhanced. Initially, the CT appearance favored benign lesions. However, the possibility of a malignant tumor can not be excluded completely. Finally, the patient was referred to the inpatient department a tumor arose from IF and underwent a selective operation. The tumor was completely removed. Histologic findings were compatible with epithelioid sarcoma. Post-operatively, the patient received 2 cycles of radiotherapy, and there was no evidence of recurrence after 6 months follow- up.

CONCLUSION

The imaging manifestations of ES are various. The anatomic structure of ITF is complex and the pathological types are various. It should be very careful in the qualitative diagnosis of tumors from the ITF, and advanced imaging techniques will be useful in imaging diagnosis.

Distal-type epitheloid sarcoma mimicking a wart in a child: A diagnosis not to be missed

Epithelioid sarcoma is a rare soft-tissue tumor that occurs mainly in children and young adults. It typically presents as a subcutaneous or deep dermal mass in distal extremities. Due to its benign-appearing clinical presentation, infrequent occurrence, and histologic similarities with other pathologies, the diagnosis of epithelioid sarcoma in its early stages can be extremely difficult and can be easily confused with benign lesions such as warts or foreign body granuloma. In this paper, we report the case of a 12-year-old boy with a distal-type epithelioid sarcoma of the hand and wish to emphasize the difficulties of diagnosing this potentially lethal tumor both clinically and histologically.

Tazemetostat for advanced epithelioid sarcoma: current status and future perspectives

Epithelioid sarcoma (ES) is an aggressive ultra-rare soft-tissue sarcoma marked by SMARCB1/INI1 deficiency. SMARCB1/INI1 deficiency leads to elevated expression of EZH2, a component of polycomb repressive complex 2, which mediates gene silencing by catalyzing H3K27me3. Tazemetostat is an oral, SAM-competitive inhibitor of EZH2, whose blockade prevents the methylation of histone H3K27, thus decreasing the growth of EZH2 mutated or over-expressing cancer cells. Tazemetostat has been approved for the treatment of patients aged 16 years and older with metastatic or advanced ES not eligible for complete resection, based on the positive results of a single-arm Phase II basket study. Tazemetostat though represents a new treatment option for ES patients, although clinical/molecular predictors of response are still to be identified. The combination of tazemetostat with other drugs like doxorubicin and immunotherapeutic agents is currently under investigation in ES patients.

Mesenchymal lesions of the vulva

Mesenchymal lesions of the vulva include site-specific entities limited to the lower genital tract, as well as a range of non-site-specific tumors that are more common at extragenital sites. Site-specific lesions include fibroepithelial stromal polyp, cellular angiofibroma, angiomyofibroblastoma, and aggressive angiomyxoma. Non-site-specific tumors that may occur in the vulva include those of smooth muscle, skeletal muscle, vascular, neural, adipocytic, and uncertain differentiation. This review discusses both site-specific and non-site-specific vulvar mesenchymal lesions including non-neoplastic proliferations, benign neoplasms, locally aggressive neoplasms with a predilection for local recurrence, neoplasms of indeterminate biologic potential, and frankly malignant neoplasms with a high risk of distant metastasis and death. Accurate diagnosis is essential for proper management, and is facilitated by correlation with clinical findings and targeted application of immunohistochemical and molecular studies.

An extremely rare elderly case of proximal epithelioid sarcoma of the vulva: case report with a review of literatures

We experienced an extremely rare case of proximal epithelioid sarcoma (PES) of the vulva in a 77-year-old woman. After history taking and physical examination, the patient was tentatively diagnosed as having Bartholin’s cyst in the right labium. Based on histopathological and immunohistochemical (IHC) findings, however, a final diagnosis of PES of the vulva was made. After receiving CyberKnife treatment, the patient survived but with recurrent episodes and poor prognosis. In conclusion, our case indicates that patients with PES of the vulva should be appropriately managed with radiotherapy after a differential diagnosis based on histopathological and IHC findings.

The natural history of epithelioid sarcoma. A retrospective multicentre case-series within the Italian Sarcoma Group

INTRODUCTION

This case-series is aimed to describe the natural history of epithelioid sarcoma (ES) and to provide insights into the differential clinical behaviour of its two variants ("classic-type" and "proximal-type"). The value of a subtype-adapted grading system based on pathological features is explored.

METHODS

Data from consecutive, primary, localised, INI1-deleted ES operated at three Italian sarcoma reference centres (1995-2015) were included. Centralised pathological review was performed. Classic-type ES was broken down into "high-grade" and "low-grade", according to number of mitoses, evidence of necrosis and nuclear atypia. Five- and 10-year overall survival (OS) and crude cumulative incidence (CCI) of local recurrence (LR) and distant metastasis (DM) were estimated.

RESULTS

Fifty-two patients were included. 5- and 10-year OS estimates were 70% and 47% in the whole series, 57% and 37% in patients with proximal-type ES, 77% and 54% in patients with classic-type ES (P = 0.02). In classic-type ES, 5- and 10-year OS was higher for low-grade (95% and 72%, respectively) than high-grade tumours (P = 0.002). 5- and 10-year CCI estimates for LR were 21% and 33% in the whole series. 5- and 10-year CCI estimates for DM were 35% and 39% in the whole series, both 28% in classic-type ES, 47% and 59% in proximal-type ES (P = 0.03).

CONCLUSIONS

Suffering from a proximal- or a classic-type is the stronger predictor of outcome in patients with localised ES, with proximal-type ES patients having lower survival due to a higher tendency toward metastatic spreading. However, the "high-grade" classic-type ES was associated with outcomes close to proximal-type ES.

Primary pleural epithelioid sarcoma of the proximal type: a diagnostic and therapeutic challenge

Epithelioid sarcoma (ES) is an uncommon soft tissue neoplasm first described in 1970. It is a unique soft tissue neoplasm of adolescents and younger adults which usually presents as a subcutaneous and deep dermal mass in the distal portions of the extremities. The proximal-type variant of this rare soft tissue neoplasm was only recently reported. The proximal form typically arise in proximal extremities and in the deep parts of pelvis, perineum and genital tract. The proximal type variant has distinct histological characteristics and aggressive clinical course as compared to the distal ES. Inactivation of INI1 has been reported in both distal and proximal variants and can help to make the diagnosis. Furthermore, the proximal variant has a possible association with malignant rhabdoid neoplasm. We describe here a case of primary pleural ES of the proximal type and highlight its diagnostic and therapeutic challenges.

Comparative Assessment of Antitumor Effects and Autophagy Induction as a Resistance Mechanism by Cytotoxics and EZH2 Inhibition in INI1-Negative Epithelioid Sarcoma Patient-Derived Xenograft

Epithelioid sarcoma (ES) is a rare mesenchymal malignancy marked by SMARCB1/INI1 deficiency. Retrospective clinical data report on the activity of anthracycline- and gemcitabine-based regimens. EZH2 inhibitors are currently being tested in clinical trials. Since comparisons of these agents are unlikely to be prospectively evaluated in the clinics, we took advantage of an INI1-deficient proximal-type ES patient-derived xenograft (PDX ES-1) to comparatively assess its preclinical antitumor activity. Mice were treated with doxorubicin and ifosfamide, singly or in combination, gemcitabine, and the EZH2 inhibitor EPZ-011989. Comparable antitumor activity (max tumor volume inhibition: ~90%) was caused by gemcitabine, EPZ-011989, and the doxorubicin-ifosfamide combination. The integration of RNAseq data, generated on tumors obtained from untreated and EPZ-011989-treated mice, and results from functional studies, carried out on the PDX-derived ES-1 cell line, revealed autophagy induction as a possible survival mechanism in residual tumor cells following EPZ-011989 treatment and identified HMGA2 as a main player in this process. Our data support the clinical use of gemcitabine and the doxorubicin-ifosfamide combination, confirm EZH2 as a therapeutic target in proximal-type ES, and suggest autophagy as a cytoprotective mechanism against EZH2 inhibition.

Practical Application of Cytology and Core Biopsy in the Diagnosis of Mesenchymal Tumors

Soft tissue neoplasms are increasingly being sampled by core needle biopsy and fine-needle aspiration (FNA), and these small biopsy specimens pose unique diagnostic challenges. Many advances in ancillary testing enable detection of characteristic immunophenotypes and molecular alterations, allowing accurate classification of soft tissue tumors in these small biopsy samples. This review outlines pattern-based diagnostic approaches to core biopsies and FNAs of soft tissue neoplasms, including formulation of practical differential diagnoses and relevant application of ancillary tests.

Loss of atrx cooperates with p53-deficiency to promote the development of sarcomas and other malignancies

The SWI/SNF-family chromatin remodeling protein ATRX is a tumor suppressor in sarcomas, gliomas and other malignancies. Its loss of function facilitates the alternative lengthening of telomeres (ALT) pathway in tumor cells, while it also affects Polycomb repressive complex 2 (PRC2) silencing of its target genes. To further define the role of inactivating ATRX mutations in carcinogenesis, we knocked out atrx in our previously reported p53/nf1-deficient zebrafish line that develops malignant peripheral nerve sheath tumors and gliomas. Complete inactivation of atrx using CRISPR/Cas9 was lethal in developing fish and resulted in an alpha-thalassemia-like phenotype including reduced alpha-globin expression. In p53/nf1-deficient zebrafish neither peripheral nerve sheath tumors nor gliomas showed accelerated onset in atrx+/- fish, but these fish developed various tumors that were not observed in their atrx+/+ siblings, including epithelioid sarcoma, angiosarcoma, undifferentiated pleomorphic sarcoma and rare types of carcinoma. These cancer types are included in the AACR Genie database of human tumors associated with mutant ATRX, indicating that our zebrafish model reliably mimics a role for ATRX-loss in the early pathogenesis of these human cancer types. RNA-seq of p53/nf1- and p53/nf1/atrx-deficient tumors revealed that down-regulation of telomerase accompanied ALT-mediated lengthening of the telomeres in atrx-mutant samples. Moreover, inactivating mutations in atrx disturbed PRC2-target gene silencing, indicating a connection between ATRX loss and PRC2 dysfunction in cancer development.

Somatic mutations in genes coding for epigenetic regulators such as ATRX are found across a diverse group of cancer types, suggesting their broad relevance in tumor induction and progression. However, tumors that have been linked to these chromatin remodelers can arise in many different molecular and cellular contexts, requiring studies with new experimental models to understand the extent and mechanisms of tumor development mediated by these regulatory proteins. Thus, we analyzed the tumor suppressive role of atrx in zebrafish that already harbored inactivating mutations of p53 and nf1. Homozygous deletion of atrx was lethal in developing fish, whereas the partial loss of this gene (atrx+/-) within the p53/nf1-deficient background led to a diverse spectrum of tumors not observed in animals that were wildtype for atrx, including epithelioid sarcoma, angiosarcoma, and rare carcinomas. Most of the cancer types we identified correspond to human tumors in the ATRX-mutant tumor sample cohort within the AACR Genie database, attesting to the relevance of our findings to human cancer. Further analysis revealed downregulation of telomerase during the lengthening of the telomeres through the ALT pathway, and disturbed function of the polycomb repressive complex 2 as key mechanistic components underlying atrx-linked tumorigenesis. These results demonstrate how a p53/nf1 compromised genetic background combined with ATRX haploinsufficiency leads to a broad spectrum of sarcomas and carcinomas associated with loss of this chromatin modulator.

FNA of epithelioid sarcoma: Curie Institute experience and critical review of the literature

BACKGROUND

Epithelioid sarcoma (ES) is a rare mesenchymal tumor that is divided into 2 types: classic and proximal. To the authors' knowledge, ES has been poorly studied in cytology, with fewer than 50 cases reported to date. The objective of the current study was to analyze the cytological and immunohistochemical information regarding 5 cases of ES.

METHODS

Five cases of ES were analyzed: 4 of proximal type and 1 of classic type. The cases were taken from 4 female patients and 1 male patient. The patients ranged in age from 10 to 75 years.

RESULTS

All smears obtained from the proximal type of ES were found to be hypercellular with a necrotic and inflammatory background. Smears from classic-type ES were hypocellular with a hemorrhagic background. Large, dispersed epithelioid cells and loosely cohesive groups of cells were most frequently noted in all cases. All cases of proximal-type ES demonstrated rhabdoid cells and marked nuclear atypia, but in only one case were rhabdoid cells found to be dominant. ES diagnoses were confirmed by immunohistochemistry in histological material. In 4 cases, epithelial marker expression was noted, whereas CD34 was found to be positive in only the classic type of ES. In 2 cases, total loss of SMARCB1/INI1 nuclear expression was observed. In the 2 SMARCB1/INI1-positive cases, loss of SMARCA2/BRM expression was observed in one case and partial loss was observed in the other case.

CONCLUSIONS

The proximal type of ES differs from the classic type by the presence of rhabdoid cells and marked nuclear atypia. A specific immunohistochemical profile demonstrating loss of SMARCB1/INI1 or other proteins from the SWI/SNF complex also may be indicative of this diagnosis.

Cytologic Features of SMARCA4-Deficient Thoracic Sarcoma: A Case Report and Comparison with Other SWI/SNF Complex-Deficient Tumors

BACKGROUND

SMARCA4-deficient thoracic sarcoma is a recently proposed entity of soft tissue tumors associated with an extremely poor prognosis. Its cytologic features have not been well described in the literature yet.

CASE

A woman in her early 30s who presented with chest pain was found to have a tumor in the right chest wall. Cytologic smears revealed numerous atypical round-to-polygonal cells appearing singly or in loosely cohesive clusters. These cells had a well-defined cell border, scant-to-moderate cytoplasm, and enlarged vesicular nuclei with prominent nucleoli. In addition, some cells with eosinophilic globular intracytoplasmic inclusions and eccentrically located nuclei, consistent with rhabdoid cells, were observed. Immunocytochemically, the cells were at least focally positive for cytokeratin CAM5.2 and CD34 and showed a significantly reduced BRG1/SMARCA4 expression. The diagnosis was confirmed by histological, immunohistochemical, and genetic analysis of a metastatic lesion to the left axillary lymph node.

CONCLUSION

Although the cytologic features of SMARCA4-deficient thoracic sarcoma are not fully unique, they are sufficiently characteristic to suspect this tumor in cases of supporting clinical and radiological features, which may promote additional immunological or molecular testing to establish a definitive diagnosis.

Anthracycline, Gemcitabine, and Pazopanib in Epithelioid Sarcoma: A Multi-institutional Case Series

Importance

Epithelioid sarcoma (ES) is an exceedingly rare malignant neoplasm with distinctive pathologic, molecular, and clinical features as well as the potential to respond to new targeted drugs. Little is known on the activity of anthracycline-based regimens, gemcitabine-based regimens, and pazopanib in this disease.

Objective

To report on the activity of anthracycline-based regimens, gemcitabine-based regimens, and pazopanib in patients with advanced ES.

Design, Setting, and Participants

Seventeen sarcoma reference centers in Europe, the United States, and Japan contributed data to this retrospective analysis of patients with locally advanced/metastatic ES diagnosed between 1990 and 2016. Local pathological review was performed in all cases to confirm diagnosis according to most recent criteria.

Exposures

All patients included in the study received anthracycline-based regimens, gemcitabine-based regimens, or pazopanib.

Main Outcome and Measures

Response was assessed by RECIST. Progression-free survival (PFS) and overall survival (OS) were computed by Kaplan-Meier method. Classic and proximal subtypes were defined based on morphology (according to 2013 World Health Organization guidelines).

Results

Overall, 115 patients were included, 80 (70%) were men and 35 (30%) were women, with a median age of 32 years (range, 15-77 years). Of the 115 patients with ES, 85 were treated with anthracycline-based regimens, 41 with gemcitabine-based regimens, and 18 with pazopanib. Twenty-four received more than 1 treatment. Median follow-up was 34 months. Response rate for anthracycline-based regimens was 22%, with a median PFS of 6 months. One complete response (CR) was reported. A trend toward a higher response rate was noticed in morphological proximal type (26%) vs classic type (19%) and in proximal vs distal primary site (26% vs 18%). The response rate for gemcitabine-based regimens was 27%, with 2 CR and a median PFS of 4 months. In this group, a trend toward a higher response rate was reported in classic vs proximal morphological type (30% vs 22%) and in distal vs proximal primary site (40% vs 14%). In the pazopanib group, no objective responses were seen, and median PFS was 3 months.

Conclusions and Relevance

This is the largest retrospective series of systemic therapy in ES. We confirm a moderate activity of anthracycline-based and gemcitabine-based regimens in ES, with a similar response rate and PFS in both groups. The value of pazopanib was low. These data may serve as a benchmark for trials of novel agents in ES.

Ultrasonography findings of proximal-type epithelioid sarcoma of the vulva: A case report

Proximal-type epithelioid sarcoma (PES) of the vulva is an exceedingly rare malignant soft tissue tumor. We herein present the case of a 41-year-old female patient who presented to our hospital with complaints of a painless mass in the right mons pubis that she had first noticed 3 years prior. Ultrasonographic (US) and color Doppler ultrasonographic (CDUS) examination revealed a solid mass with well-defined, homogeneous hypoechoic structure and quite hypervascular on CDUS. The results of the immunohistochemical examination confirmed the diagnosis of vulvar PES (myxoid variant). The patient was treated with wide local excision and remained recurrence- and metastasis-free at 9 months postoperatively. Although cases of PES in the pelvic region had been previously reported, to the best of our knowledge, the US or CDUS findings of PES of the vulva have not been described to date.

SMARCA4-deficient undifferentiated uterine sarcoma (malignant rhabdoid tumor of the uterus): a clinicopathologic entity distinct from undifferentiated carcinoma

Small cell carcinoma of the ovary, hypercalcemic type is a rare, aggressive malignancy which usually occurs in young women and is characterized by mutations in SMARCA4, with few other alterations. We recently encountered uterine tumors with morphologic, immunohistochemical, and genetic similarities to small cell carcinoma of the ovary, hypercalcemic type. Herein we report the clinicopathologic and molecular features (using a targeted massively parallel sequencing [MPS] assay) of these tumors. The cases were diagnosed on cervical and endometrial biopsies (n = 2, 34, and 29 years) or hysterectomy and bilateral salpingo-oophorectomy (n = 3, 25, 33, and 58 years). The tumors were composed of sheets of large atypical epithelioid cells with prominent rhabdoid morphology, indistinguishable from the "large cell" variant of small cell carcinoma of the ovary, hypercalcemic type. In three cases, the ovaries were pathologically examined to exclude a primary ovarian malignancy. Immunohistochemically, four of four cases showed SMARCA4 loss, and were negative or only focally positive for keratins, EMA, and claudin-4. One of three cases was positive for WT-1. Targeted MPS was successfully performed on 4 of 5 tumors, and showed recurrent mutations in SMARCA4, with few other alterations. Of the cases diagnosed on hysterectomy, all had extensive lymphovascular invasion, extra-uterine spread, and marked infiltrative growth. These tumors were uniformly aggressive; all patients died of disease (median survival 7 months, range 1-43 months). We propose this entity be called "SMARCA4-deficient undifferentiated uterine sarcoma (malignant rhabdoid tumor of the uterus)", a term which describes both the tumor's underlying molecular abnormality and its morphology. Its unique clinicopathologic and molecular features differentiate it from other related malignancies, including undifferentiated endometrial carcinoma, small cell carcinoma of the ovary (hypercalcemic type), and epithelioid sarcoma. We review and discuss previously reported "rhabdoid tumors of the uterus;" while they are a heterogenous group of tumors, some of them are likely examples of this entity. Correctly identifying cases of SMARCA4-deficient uterine sarcoma from histologic mimics is important as it may have prognostic, predictive, and germline implications.

Primary intra-articular epithelioid sarcoma of the knee: Unusual presentation of a rare entity

We report a case of a 60-year-old female with severe and progressive pain of her right knee. Physical therapy, pain medication, and arthroscopic debridement were unsuccessful. Finally, pathological examination revealed an intra-articular epithelioid sarcoma, a rare tumor in an atypical location. Patient died within 5 months after initial admission. Despite this unusual clinical course and presentation, we would like to share the valuable clinical lessons we learned from this case. Introduction of a coordinating physician in combination with a multidisciplinary treatment regarding optimal pain management should optimize treatment results in future patients.

Proximal-type epithelioid sarcoma of the oral cavity: a case report and literature review

Proximal-type epithelioid sarcoma (PES) is an exceedingly rare malignant tumor of soft tissue; PES within the oral cavity is even rarer. Pathologic examination is the primary diagnostic modality, and surgical treatment is recommended as the preferred method for the treatment of PES. Currently, there is a paucity of literature that systematically reports on PES in the oral cavity. Here, we describe a 42-year-old man with PES in the oral cavity, which showed positivity for vimentin, cytokeratin, CD31, S-100 but did not express BCL-2, HMB-45, or desmin. We performed a wide excision and neck dissection, and then used the free anterolateral thigh flap to reconstruct the defect in the soft tissue. Furthermore, we review the current literature with regard to diagnosis and treatment of PES.

Epithelioid sarcoma in the chest wall: a case report and literature review

BACKGROUND

Epithelioid sarcoma (ES) is a rare variant of soft tissue sarcoma. The proximal type of ES occurs in various locations. We present a resected case with proximal-type ES that occurred in the chest wall and discuss the relevant literature.

CASE PRESENTATION

A 47-year-old woman was referred for a 6-month history of a right anterior chest mass with tenderness. Chest computed tomography showed an invasive chest wall mass with calcification surrounding the third rib. Aspiration biopsy cytology suggested malignancy. We performed wide resection, including the middle part of the pectoralis major muscle, the pectoralis minor muscle, the third and fourth ribs, and reconstruction of the chest wall, using a 2-mm polytetrafluoroethylene patch. Severe deformation of the chest wall was avoided. Postoperative physical therapy of the shoulder was effective for the continuous pain and weakness of the arm. She has remained alive for 1 year and 10 months without recurrence. Our literature review showed five previously reported cases of ES in the chest wall, and all of these were surgically resected. Two of these patients suffered from frequent local recurrence and died of disease.

CONCLUSIONS

ES in the chest wall is rare. Previous reports have indicated that surgical resection with tumor-free margins is essential for treatment. We performed complete resection of the tumor in our case, and a polytetrafluoroethylene patch was effective for reconstructing the deficit in the chest wall.

Can radical margins improve prognosis in primary and localized epithelioid sarcoma of the extremities?

INTRODUCTION

Epithelioid sarcoma (ES) has a tendency to locally recur, spread proximally, and metastasize, in particular to lymphnodes and lungs. The aim of this report is to study the role of surgery and the extent of margins required for optimal management of patients with localized epithelioid sarcoma of the extremities.

MATERIAL AND METHODS

We retrospectively evaluated 77 patients affected by ES of the extremities treated at two different Institutions.

RESULTS

Twenty-two patients had metastasis at diagnosis. Estimated survival was 65.5% at 5 years and 50.9% at 10 years, with a better prognosis in patients with localized disease at diagnosis (P < 0.001). Among patients with localized disease, a significantly better survival was found in patients with primary tumors in which radical surgical margins were achieved (P = 0.043). Among 47 patients presenting with primary tumors, local recurrence-free rate was 72.9% at 5 years, and 61.9% at 10 years, with a better local control achieved in patients with radical margins were achieved (P = 0.026).

DISCUSSION

We believe that the best approach to improve both local control and survival is to aim for radical margins in patients with primary tumors. Therefore, the best chance for cure is if the first treatment is the right treatment, which we believe to be radical margins.

Reduced argininosuccinate synthetase expression in refractory sarcomas: Impacts on therapeutic potential and drug resistance

Background

Treating drug-resistant sarcomas remains a major challenge. The present study aimed to identify a novel therapy for drug-resistant sarcomas based on metabolic errors involving argininosuccinate synthetase1 (ASS1).

Results

ASS1 expression was reduced in Dox-resistant sarcoma cells. Immunohistochemistry and real-time PCR showed an inverse correlation between ASS1 and P-gp expressions. The inhibition of cellular proliferation with G1-arrest was shown to lead to autophagy with arginine deprivation. In addition, the combination of an autophagy inhibitor plus arginine deprivation was more effective than arginine deprivation alone. In cells with suppressed ASS1 expression, P-gp expression was upregulated as compared to that in negative controls.

Discussion

These results indicate that the reduced ASS1 expression in Dox-resistant sarcomas may contribute to drug resistance in association with the expression of P-gp. ASS1 deficiency is a potential target for novel drug therapies. The combination of arginine-deprivation therapy and an autophagy inhibitor may have anti-tumor effects in refractory sarcomas.

Methods

We assessed the expressions of ASS1 and P-glycoprotein (P-gp) in clinical specimens and cell lines of osteosarcoma (KHOS), doxorubicin (Dox)-resistant osteosarcoma (KHOS_R2), epithelioid sarcomas (ES-X and VAESBJ) and alveolar soft part sarcoma (ASPS-KY). Each cell line was cultured in arginine-containing and arginine-free media. Cell growth was assessed using an XTT assay and flow cytometry. We analyzed the induction of autophagy in arginine-free medium. Moreover, we assessed the expression of P-gp after suppressing ASS1 in Dox-sensitive cells (MCF-7 and KHOS) and after transfecting ASS1 into Dox-resistant cells (ES-X, VAESBJ, ASPS-KY and KHOS_R2).

SMARCB1-deficient Tumors of Childhood: A Practical Guide

The SMARCB1 gene ( INI1, BAF47) is a member of the SWItch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeling complex, involved in the epigenetic regulation of gene transcription. SMARCB1 acts as a tumor suppressor gene, and loss of function of both alleles gives rise to SMARCB1-deficient tumors. The prototypical SMARCB1-deficient tumor is the malignant rhabdoid tumor (MRT) which was first described in the kidney but also occurs in soft tissue, viscera, and the brain (where it is referred to as atypical teratoid rhabdoid tumor or AT/RT). These are overwhelmingly tumors of the very young, and most follow an aggressive and ultimately lethal course. Morphologically, most but not all contain a population of "rhabdoid" cells, which are large cells with abundant cytoplasm, perinuclear spherical inclusions, and eccentric vesicular nuclei with large inclusion-like nucleoli. MRT immunohistochemistry reveals complete loss of SMARCB1 nuclear expression, and molecular analysis confirms biallelic SMARCB1 inactivation in the vast majority. Rare AT/RTs have loss of SMARCA4, another SWI/SNF member, rather than SMARCB1. With the widespread adoption of SMARCB1 immunohistochemistry, an increasing number of SMARCB1-deficient tumors outside of the MRT-AT/RT spectrum have been described. In addition to MRT and AT/RT, pediatric tumors with complete loss of SMARCB1 expression include cribriform neuroepithelial tumor, renal medullary carcinoma, and epithelioid sarcoma. Tumors with variable loss of SMARCB1 expression include subsets of epithelioid malignant peripheral nerve sheath tumor, schwannomas arising in schwannomatosis, subsets of chordomas, myoepithelial carcinomas, and sinonasal carcinomas. Variable and reduced expression of SMARCB1 is characteristic of synovial sarcoma. In this review, the historical background, clinical characteristics, morphology, immunohistochemical features, and molecular genetics most germane to these tumors are summarized. In addition, familial occurrence of these tumors (the rhabdoid tumor predisposition syndrome) is discussed. It is hoped that this review may provide practical guidance to pathologists encountering tumors that have altered expression of SMARCB1.

Clinicopathological analysis of myxoid proximal-type epithelioid sarcoma

Proximal-type epithelioid sarcoma (ES) with a diffuse myxoid stroma is rare. Here, we report the case of a 33-year-old man with a perineal mass. Imaging showed the presence of a poorly demarcated 6.9 × 5.3-cm mass in the subcutaneous perineal region. Macroscopic examination showed that the resected tissues were partially necrotic. Histological examination showed that the tumor comprised numerous large or pleomorphic epithelioid cells with large vesicular nuclei and prominent nucleoli. A clear background of necrosis and inflammatory exudates was also present. Immunohistochemical examination showed that the tumor cells were positive for vimentin and CD34 - both of which were expressed throughout the cytoplasm - but typically did not express nuclear INI1 (SMARCB1). Hematoxylin-eosin staining (HE staining) showed that the mucin content of the tumor was approximately 80%. The patient was diagnosed with proximal-type ES with myxoid features. The patient died due to disease progression after 2 months of follow-up and without undergoing further treatment in our department. To our knowledge, only 2 cases of proximal-type ES with diffuse myxoid stroma have been reported. Proximal-type ES is rare, and this is the first case report of proximal ES with myxoid features in the perineal area.