"Proximal-type" epithelioid sarcoma, a distinctive aggressive neoplasm showing rhabdoid features. Clinicopathologic, immunohistochemical, and ultrastructural study of a series

Proximal and Classic Epithelioid Sarcomas are Distinct Molecular Entities Defined by MYC/GATA3 and SOX17/Endothelial Markers, Respectively

Epithelioid sarcoma (ES) is a rare tumor hallmarked by the loss of INI1/SMARCB1 expression. Apart from this alteration, little is known about the biology of ES. Despite recent advances in treatment, the prognosis of ES remains unsatisfactory. To elucidate the molecular underpinnings of ES, and to identify diagnostic biomarkers and potential therapeutic vulnerabilities, we performed an integrated omics profiling (RNA sequencing and methylation array) of 24 primary, untreated ESs. Transcriptome and methylome analysis identified 2 distinct molecular clusters that essentially corresponded to the morphologic variants of ES, classic ES (C-ES) and the more aggressive proximal ES (P-ES). The P-ES group was characterized by hyperactivation of GATA3 and MYC pathways, with extensive epigenetic rewiring associated with EZH2 overexpression. Both DNA methylation and gene expression analysis indicated a striking similarity with the "MYC subgroup" of atypical teratoid/rhabdoid tumor, another SMARCB1-deficient tumor, implying a shared molecular background and potential therapeutic vulnerabilities. Conversely, the C-ES group exhibited an endothelial-like molecular profile, with expression of vascular genes and elevated proangiogenic SOX17 signaling. Immunohistochemistry validated the overexpression of the chromatin regulators GATA3 (9/12 vs 0/16) and EZH2 (7/7 vs 2/6) in P-ESs, and of the vascular factors SOX17 (8/8 vs 1/10) and N-cadherin (5/9 vs 0/10) in C-ESs. Therefore, these molecules emerge as potential diagnostic tools to fill the gap represented by the lack of ES subtype-specific biomarkers. In summary, our study shows that P-ES and C-ES represent distinct molecular entities defined by MYC/GATA3 and SOX17/endothelial molecular traits, respectively. Besides providing insights into the biology of ES, our study pinpoints subtype-specific biomarkers and potential therapeutic vulnerabilities.

Expression of Forkhead Box M1 and Anticancer Effects of FOXM1 Inhibition in Epithelioid Sarcoma

Epithelioid sarcoma (ES) is a rare aggressive sarcoma that, unlike most soft-tissue sarcomas, shows a tendency toward local recurrence and lymph node metastasis. Novel antitumor agents are needed for ES patients. Forkhead box transcription factor 1 (FOXM1) is a member of the Forkhead transcription factor family and is associated with multiple oncogenic functions; FOXM1 is known to be overexpressed and correlated with pathogenesis in various malignancies. In this study, we immunohistochemically analyzed FOXM1 expression levels and their clinical, clinicopathologic, and prognostic significance in 38 ES specimens. In addition, to investigate potential correlations between FOXM1 downregulation and oncologic characteristics, we treated ES cell lines with thiostrepton, a naturally occurring antibiotic that inhibits both small interfering RNA (siRNA) and FOXM1. In the analyses using ES samples, all 38 specimens were diagnosed as positive for FOXM1 by immunohistochemistry. We separated specimens into high (n = 19) and low (n = 19) FOXM1-protein expression groups by staining index score, and into large (n = 12), small (n = 25), and unknown (n = 1) tumor-size groups using a cutoff of 5 cm maximum diameter. Although there were significantly more samples with high FOXM1 expression in the large tumor group (P = .013), there were no significant differences with respect to age (P = 1.00), sex (P = .51), primary site of origin (P = .74), histologic subtypes (P = 1.00), depth (P = .74), or survival rate (P = .288) between the high and low FOXM1-protein expression groups. In the in vitro experiments using ES cell lines, FOXM1 siRNA and thiostrepton successfully downregulated FOXM1 mRNA and protein expression. Furthermore, downregulation of FOXM1 inhibited cell proliferation, drug resistance against chemotherapeutic agents, migration, and invasion and caused cell cycle arrest in the ES cell lines. Finally, cDNA microarray analysis data showed that FOXM1 regulated cIAP2, which is one of the apoptosis inhibitors activated by the TNFα-mediated NF-κB pathway. In conclusion, the FOXM1 gene may be a promising therapeutic target for ES.

Translational Aspects of Epithelioid Sarcoma: Current Consensus

Epithelioid sarcoma (EpS) is an ultra-rare malignant soft-tissue cancer mostly affecting adolescents and young adults. EpS often exhibits an unfavorable clinical course with fatal outcome in ∼50% of cases despite aggressive multimodal therapies combining surgery, chemotherapy, and irradiation. EpS is traditionally classified in a more common, less aggressive distal (classic) type and a rarer aggressive proximal type. Both subtypes are characterized by a loss of nuclear INI1 expression, most often following homozygous deletion of its encoding gene, SMARCB1-a core subunit of the SWI/SNF chromatin remodeling complex. In 2020, the EZH2 inhibitor tazemetostat was the first targeted therapy approved for EpS, raising new hopes. Still, the vast majority of patients did not benefit from this drug or relapsed rapidly. Further, other recent therapeutic modalities, including immunotherapy, are only effective in a fraction of patients. Thus, novel strategies, specifically targeted to EpS, are urgently needed. To accelerate translational research on EpS and eventually boost the discovery and development of new diagnostic tools and therapeutic options, a vibrant translational research community has formed in past years and held two international EpS digital expert meetings in 2021 and 2023. This review summarizes our current understanding of EpS from the translational research perspective and points to innovative research directions to address the most pressing questions in the field, as defined by expert consensus and patient advocacy groups.

A unique case of epithelioid sarcoma involving the mandibular alveolar mucosa

Epithelioid sarcoma (ES) is an infrequent, malignant, mesenchymal, soft-tissue neoplasm of uncertain histogenesis characterized by epithelioid cytomorphology. The lack of SMARCB1/INI1 (Integrase interactor 1) expression typifies this pathology. It usually presents as a painless, indolent, slowly enlarging lesion or rarely as an aggressive growth. Epithelioid sarcoma affects mostly pediatric patients or young adults. It recurs quite frequently and possesses a high degree of metastatic potential. Two predominant histomorphologic patterns include classic/conventional type and proximal types. Epithelioid sarcoma immunohistochemically shows vimentin, cytokeratin, epithelial membrane antigen, CD34 positivity, and negative staining with S100 and desmin. Management is generally multimodal, including wide surgical resection, radiotherapy, and chemotherapy. To date, to our knowledge, only 11 instances of head and neck ES have been reported in the literature. Our case deals with the diagnosis of intraoral ES in a 55-year-old female patient, probably the first one to involve the mandibular mucosa, based on relevant clinical-radiologic-pathologic-immunohistochemical findings.

Soft tissue tumours of the penis. The 30-year Istituto Nazionale Tumori di Milano experience

Objective

Small series and individual cases of penile soft tissue tumours are reported in the literature: these are rare tumours that represent less than 5% of all penile tumours.

Methods

Penile soft tissue tumours were collected from the archive of the Department of Pathology at the Istituto Nazionale dei Tumori of Milan between January 1990 and October 2021. All available medical records were retrieved and reviewed to obtain clinical information.

Results

Our series refers to the 30-year experience of highlighting the heterogeneity in the presentation and microscopic features of these rare sarcomas. 18 penile soft tissue tumours are described, 4 benign and 14 malignant. The mean age at diagnosis was 58.2 years (range 24-96 years) and 53.6 years among malignancies (range 24-89). The most frequent histotype was Kaposi's sarcoma (nr = 4) and very unusual histotypes were observed, namely low-grade fibromyxoid sarcoma, synovial sarcoma, proximal type epithelioid sarcoma and the first reported case of dedifferentiated liposarcoma of the penis.

Conclusions

Among sarcomas of the genitourinary tract, tumours of the soft tissues of the penis are the rarest. Penile sarcomas can present at a young age. Kaposi's sarcoma in HIV-negative patients has a favorable outcome, while deep sarcomas have an aggressive behavior and poor prognosis.

Abdominal rhabdoid tumor presenting with symptomatic spinal epidural compression in a newborn. A case report

The occurrence of an abdominal tumor invading the spinal canal and causing symptoms of epidural compression is rare in an infant, and exceptional at birth. Peripheral neuroblastic tumors are by far the most common cause. Emergency chemotherapy is commonly curative, though permanent sequelae are possible. Although other malignancies may be involved, no case of rhabdoid tumors at birth has been reported. We describe the case of a neonate who presented symptoms of spinal epidural compression at birth secondary to a rhabdoid tumor. As expected with this highly malignant tumor, the patient experienced a rapidly progressive clinical course and died within three months of diagnosis.

Combination of four pedicled flaps for multilayer reconstruction of massive pelvic defect: A case report

Tumors affecting the perineal region are a subtle and difficult to diagnose type of malignancy. In particular, soft tissue sarcomas (STS) may be already very large at time of diagnosis, thus impairing a normal life. In such severe cases, debulking surgery is the only possibility to offer the patient an acceptable quality of life again. These procedures inevitably result in massive defects. Depending on the affected area, there are different reconstructive options available so far, and sometimes a combination of multiple flaps is required. With the present report, we would like to share our experience with a complex genital and perineal defect. A 75-year-old patient presenting a massive epithelioid sarcoma in the ischio-rectal and anal fossae underwent a surgical excision with safe margins, which included the resection of the external genitalia, the pubis, and the rectum. The end result of this procedure was a massive defect measuring 31 cm (length) × 8 cm (width) × 6 cm (depth). To accomplish the requirements of this particular case we planned to utilize mostly the nearby tissues. The reconstruction was performed layer by layer. We resorted to a pedicled chimeric anterolateral thigh (ALT) flap measuring 8 cm × 6 cm, with a large amount of the vastus lateralis (20 cm × 8 cm) to fill the deeper defect, and a duplicated fascia lata (20 cm × 6 cm) to restore the abdominal support of the pubis. Then the external coverage was completed combining a pedicled superficial circumflex (SCIP) flap measuring 9 cm × 8 cm, a pedicled gracilis flap measuring 27 cm × 4 cm and a pedicled posteromedial thigh (PMT) flap measuring 22 cm × 8 cm harvested in vertical fashion. The postoperative course was uneventful, and at 6 months follow up the reconstructive result was successful with a stable soft tissue coverage and no complaints from the patient. With the present case report, we would like to show the importance of mastering different reconstructive procedures, whose combination might be the only solution to cover very large and complex defects.

Mesenchymal Neoplasms of the Liver

Mesenchymal neoplasms of the liver can be diagnostically challenging, particularly on core needle biopsies. Here, I discuss recent updates in neoplasms that are specific to the liver (mesenchymal hamartoma, undifferentiated embryonal sarcoma, calcifying nested stromal-epithelial tumor), vascular tumors of the liver (anastomosing hemangioma, hepatic small vessel neoplasm, epithelioid hemangioendothelioma, angiosarcoma), and other tumor types that can occur primarily in the liver (PEComa/angiomyolipoma, inflammatory pseudotumor-like follicular dendritic cell sarcoma, EBV-associated smooth muscle tumor, inflammatory myofibroblastic tumor, malignant rhabdoid tumor). Lastly, I discuss metastatic sarcomas to the liver, as well as pitfalls presented by metastatic melanoma and sarcomatoid carcinoma.

Primary Epithelioid Sarcoma of the Conchal Bowl in a 64-Year-Old Male: A Case Report and Review of the Literature

ABSTRACT

Epithelioid sarcoma (ES) is a distinctive malignant mesenchymal neoplasm with atypical epithelioid cells palisading around a central zone of necrosis. ES is a rare entity even in soft tissue pathology. Immunohistochemically, tumors usually show diffuse epithelial membrane antigen and cytokeratin expression and loss of nuclear INI1 (SMARCB1) expression. Here, we report a case of a 64-year-old man with ES arising in the left conchal bowl. Given the clinical presentation including patient's age, sun-exposed area of skin, and slow-growing, asymptomatic, small pink pearly papule, this patient was initially misdiagnosed with basal cell carcinoma clinically and treated with topical imiquimod at an outside facility. The lesion continued to grow and eventually became symptomatic despite the treatment after which biopsy was obtained. Despite the unusual anatomic site and the patient's age, the microscopic and immunohistochemical findings were characteristic of conventional-type ES. Our case shows that ES can arise in rare locations and in older adults where it may be more easily misdiagnosed clinically and pathologically as a nonmelanoma skin cancer.

Imaging findings of primary epithelioid sarcoma of adrenal gland: a case report and literature review

Epithelioid sarcoma (ES) is a rare soft tissue malignant tumor with an uncertain histogenetic origin. It usually arises in soft tissues of the extremities, while ES in adrenal gland is extremely rare. There is no special clinical manifestation in the early stage, so it may be misdiagnosed and delay the treatment. We reported a 69-year-old male with an adrenal ES. The tumor was completely resected, and two months later, positron emission tomography-computed tomography(PET/CT) noted recurrence at the tumor bed and multiple metastases. The patient has been treated with chemotherapy with good effects. We summarize the radiological findings and immunohistochemical indexes of primary epithelioid sarcoma of adrenal gland, which may be useful to promote disease awareness and help to distinguish among other lesions.

Epithelioid and spindle rhabdomyosarcoma with TFCP2 rearrangement in abdominal wall: a distinctive entity with poor prognosis

BACKGROUND

Epithelioid and spindle rhabdomyosarcoma (ES-RMS) with TFCP2 rearrangement is a recently discovered rare variant of rhabdomyosarcoma composed of epithelioid and spindle cells, because it shows extraordinarily adverse prognosis and is easily misdiagnosed as other epithelioid or spindle cell tumors.

METHODS

A rare case of ES-RMS with TFCP2 rearrangement was presented and English literatures in Pubmed online up to 01 July 2022 were gathered by two authors for a systematic review according to the inclusion and exclusion criteria.

CASE PRESENTATION/RESULTS

We report a case of ES-RMS in an early 30s-years-old female, the neoplastic cells are remarkably immunoreactive with CK(AE1/AE3), and partially with ALK protein. Unexpectedly, the tumor shows TFCP2 rearrangement with coexistence of increased copy numbers of EWSR1 and ROS1 gene and MET gene mutation. Besides, Next-generation sequencing for genetic mutational profiling revealed frequent MET exon14 mutations in chromosome 7, most of which are C > T nonsynonymous SNV, and exon42 of ROS1 in chromosome 6 showed frequent G > T mutation up to 57.54%. In addition, neither MyoD1 mutation nor gene fusions were detected. Moreover, the patient shows high tumor mutational burden (TMB) up to 14.11 counts/Mb. Finally, as many cases of ES-RMS including our case had local progression or metastasis, we find, similar to epithelioid rhabdomyosarcoma (median survival time is 10 month), ES-RMS shows a more aggressive behavior and adverse prognosis (median survival time is 17 month) than spindle cell/sclerosing rhabdomyosarcoma (median survival time is 65 month) according previous studies.

CONCLUSIONS

ES-RMS with TFCP2 rearrangement is a rare malignant tumor and easily confused with other epithelioid or spindle cell tumors, it may harbor additional gene alteration in addition to TFCP2 rearrangement, such as MET mutation, increased copy numbers of EWSR1 and ROS1 gene, high TMB. Most importantly, it may show very poor outcome with extensive metastasis.

Epithelioid and Clear Cell Solitary Fibrous Tumors: Clinicopathologic, Immunohistochemical, and Molecular Genetic Study of 13 Cases

Solitary fibrous tumors (SFTs) are ubiquitous soft tissue neoplasms known for their protean histology and potentially aggressive behavior. Although most cases are composed of a monotonous proliferation of spindle cells, some tumors show unusual cytologic features. We have studied 13 SFTs that were characterized by a predominant population of round epithelioid cells with abundant eosinophilic cytoplasm and clear cell changes. The tumors occurred in 8 women and 5 men, aged 36 to 80 years (mean=63 y), and were located within the orbit (3), lower extremity (3), retroperitoneum (2), abdominal cavity (2), and superficial soft tissues of the neck, pelvis, and pubis (1 each). The tumors measured from 3.5 to 24.5 cm. Using a risk assessment system, 6 cases were stratified as low-risk tumors; 3 of these showed no evidence of recurrence or metastases from 6 to 18 years, and 1 tumor in the orbit recurred and led to the patient's demise. Five cases were of intermediate risk; clinical follow-up showed no evidence of recurrence or metastases from 3 to 4 years in 3 patients, and 1 patient suffered a recurrence 4 years after diagnosis. Two cases were high risk; 1 patient died after 1 year and the second patient experienced local recurrence at 4 years. Immunohistochemical studies showed nuclear positivity for STAT6 in 10 cases. CD34 immunohistochemistry was positive in 11 cases. A NAB2::STAT6 rearrangement was present in all cases. Epithelioid and clear cell SFT should be considered in the differential diagnosis of soft tissue neoplasms with epithelioid and clear cell morphology.

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.

Epithelioid sarcoma and its outcome: a retrospective analysis from a tertiary care center in North India

Aim

Clinicopatholgical findings and outcomes in epithelioid sarcoma (ES) patients.

Materials & methods

ES patients registered in sarcoma clinic from 2015 to 2021.

Results

There were 20 patients with median age of 26 years. Majority had distal ES (70%) and advanced disease (85%). In patients with advanced disease lymph nodes were involved in 65%, lungs in 58% and others in 35%. Among 14 patients who underwent biopsy outside our institute, nine (64.2 %) had been initially misdiagnosed. Response rates to doxorubicin (n = 12), pazopanib (n = 6), gemcitabine/docetaxel (n = 5), tazemetostat (n = 3) and immunotherapy (n = 2) used in various lines were 16, 16, 20, 33 and 0%, respectively.

Conclusion

Our patients had an advanced-stage and distal ES, with a modest response to chemotherapy.

Prognostic nomogram in patients with epithelioid sarcoma: A SEER-based study

OBJECTIVE

The prognostic factors for patients with epithelial sarcoma remain unclear. The study aims to develop a practical clinical nomogram that predicts prognosis in patients with ES using the Surveillance, Epidemiology, and End Results (SEER) database.

METHODS

We extracted clinical data from 2004 to 2015 from the SEER database about patients with ES. All patients were randomly divided into training cohort and validation cohort. Kaplan-Meier analyses were used to compare outcomes between different subgroups. In order to estimate the chance of survival for patients with ES, we developed a nomogram. Nomogram performance was evaluated by discrimination and calibration. Additionally, an analysis of decision curves was conducted to evaluate the clinical usefulness of this newly developed model.

RESULTS

In the primary cohort,320 met the inclusion criteria to be entered into this study. The median OS was 66.000 months (range 34.704 to 94.296 months), and the 1-, 3-, and 5-year OS rates were 70.7%, 56.1%, and 50.4%, respectively. For the validation cohort, we studied 136 consecutive patients. Age, primary site, grade, AJCC (American Joint Committee on Cancer) T, AJCC M, and surgery were included in the nomogram. The C-index values for the training set and validation set were 0.817 and 0.832, respectively. The calibration plots showed good agreement between the prediction and the observation. Based on the clinical decision curve, the model has a good clinical net benefit for ES patients.

CONCLUSIONS

It is the first study that developed an effective survival prediction model for patients with ES. Using this nomogram can assist in clinical decision-making as it has satisfactory accuracy. Even so, additional external validation is needed.

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.

A Subset of SMARCB1 (INI-1)-deficient vulvar neoplasms express germ cell markers

AIMS

SMARCB1 (INI-1)-deficient vulvar neoplasms comprise a group of rare tumours that include epithelioid sarcoma (ES), myoepithelial carcinoma (MEC), the recently described myoepithelioma-like tumour of the vulvar region (MELTVR), and sarcomas that are difficult to classify. It has been suggested that so-called vulvar yolk sac tumours (YST) may represent morphologic variants of SMARCB1-deficient tumours; thus, we investigated the immunoreactivity of germ cell markers in SMARCB1-deficient vulvar neoplasms.

METHODS AND RESULTS

Ten SMARCB1-deficient vulvar neoplasms were stained with germ cell tumour markers (SALL4, glypican-3, OCT3/4, and AFP) and re-reviewed for morphologic features. The tumours occurred in adult females (median age 41 years) and included ES (n = 7), MELTVR (n = 2), and MEC (n = 1). All cases showed loss of SMARCB1 expression. Four cases (40%) were focally positive for SALL4 in areas with morphology of typical-appearing ES. One of these cases also showed focal staining for OCT3/4. One ES showed a transition from typical-appearing ES to YST-like morphology, with diffuse expression of SALL4 and glypican-3, and focal expression of AFP, in these latter areas. All other tested cases were negative for AFP.

CONCLUSION

Our study reveals that SALL4, glypican-3, and OCT3/4 are positive in a subset of SMARCB1-deficient vulvar neoplasms, which may pose a diagnostic challenge and result in consideration of a germ cell tumour. We also highlight a case with transition from ES to YST-like morphology, lending further support that YSTs of the vulva are somatically derived SMARCB1-deficient neoplasms and do not represent true germ-cell neoplasia.

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.

Myoepithelial carcinoma of soft tissue is a diagnostic challenge on fine-needle aspiration: Case report and review of literature

Myoepithelial carcinoma (MEC) of soft tissue, also known as malignant myoepithelial tumor, is an uncommon malignancy. Cytologic diagnosis of this entity is challenging due to its rarity and heterogeneous morphology. We report a case of MEC in a 22-year-old man, who presented with a 6.5 cm soft tissue mass on his right distal forearm that has been enlarging over the past 3 months. Ultrasound-guided fine-needle aspiration (FNA) revealed abundant isolated neoplastic cells ranging from spindled cells to epithelioid and plasmacytoid morphology in a myxoid background. These cells showed moderate cytologic atypia characterized by high-nuclear/cytoplasmic ratio, irregular nuclear contours, and prominent nucleoli. The cytoplasm varied from dense to vacuolated and occasionally rhabdoid with intracytoplasmic inclusions. Scattered bi- and multinucleated cells were identified. A diagnosis of high-grade malignancy was made with the differential diagnosis including rhabdomyosarcoma and melanoma. A subsequent core biopsy of the tumor showed immunoreactivity for pan-cytokeratins, calponin, p63, and smooth muscle actin. INI-1 was lost. SOX-10 and Melan-A were negative. Molecular studies showed loss of SMARCB1 (INI-1) and CDKN2A. Gene fusion studies did not detect any fusion. A diagnosis of soft tissue MEC was made which is a challenge on FNA due to several cytologic mimickers including rhabdomyosarcoma, epithelioid sarcoma, extrarenal rhabdoid tumor, extra-axial chordoma and melanoma. Recognition of the biphasic cell population in a myxoid background and a battery of immunohistochemical stains are crucial for accurate diagnosis.

Proximal-type epithelioid sarcoma of vulva – Case series of a rare tumor

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Proximal-type Epithelioid sarcoma of the vulva is a rare, aggressive soft tissue neoplasm seen in young and middle-aged females.

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Biopsy of the lesion with immunohistochemistry aids in diagnosis and differentiating from benign mimics.

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Loss of INI1 is characteristic and seen in the majority.

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Surgery is the mainstay of management in localized disease.

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Recently, Tazemetostat has obtained accelerated FDA approval for use in locally advanced and metastatic settings.

Epithelioid sarcoma (ES) is rare and aggressive soft tissue neoplasm characterized by tumor cells showing epithelioid morphology and immunohistochemically, characteristic loss of INI1/ SMARCB1 in most cases. The proximal-type ES usually involves the deeper soft tissues of the vulva or perineum is an extremely rare entity with diagnostic challenges. Surgery is the mainstay of treatment in localized diseases. Radiation and chemotherapy are used in the advanced and metastatic setting, however, their role in the adjuvant setting is uncertain. Anthracycline and gemcitabine-based chemotherapy are given in metastatic and recurrent tumors. We report 4 cases of ES treated over a period of 6 years at our center. All the cases initially presented at a local hospital with vulvar swelling with a benign mimic (3/4) or squamous cell carcinoma (1/4). The median age of diagnosis was 34 years (range 17–80). The diagnosis was established with epithelioid morphology of tumor cells and immunohistochemically characteristic loss of INI1/SMARCB1 in all cases. 3 cases were treated with upfront surgery and two of them received adjuvant radiotherapy. One case received upfront palliative therapy due to lung metastasis at the time of presentation. On median follow-up of 24 months (2–63), 2 cases were disease-free. One case had a recurrence in the lungs and chest wall after a disease-free interval of 63 months. She underwent surgical excision of metastatic deposits, however developed second lung recurrence after 3 months and is being treated with Adriamycin-based chemotherapy. All patients are alive at the last follow-up.

Successful management of vulvar proximal-type epithelioid sarcoma in pregnancy

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Vulvar proximal-type epithelioid sarcoma during pregnancy is extremely rare.

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Immediate and agressive treatment is essential even in pregnancy, and vulvectomy during pregnancy is considered safe.

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Further reserch is required to discuss about the effectiveness of adjuvant therapy.

Vulvar proximal-type epithelioid sarcoma during pregnancy is extremely rare; only two reports are available to date. Herein, we describe a 36-year-old woman who presented with a pigeon-egg-sized solid mass with cystic component on the left labia majora at 18 weeks of gestation. The patient underwent tumor resection at 23 weeks of gestation and was diagnosed with epithelioid sarcoma, proximal-type. At 29 weeks of gestation, elective cesarean section, radical local resection of the vulva and vagina, and inguinal lymphadenectomy were performed. After surgery, she underwent six courses of adjuvant chemotherapy (doxorubicin 60 mg/m² and cisplatin 50 mg/m²) every four weeks. The patient and her baby survived with neither recurrence nor complications until 5 years. Aggressive management for proximal-type epithelioid sarcoma, such as early termination of pregnancy and operation, can improve maternal outcomes.

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.

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.

Epithelioid sarcoma: A single-institutional retrospective cohort study of 36 cases

BACKGROUND

Few studies have focused on the correlation between the clinical variables and the survival in Epithelioid Sarcoma (ES). The aim of this study was to investigate the relevant clinical variables influencing the survival of ES patients.

METHODS

From March 2000 to April 2018, 36 patients (median age, 38 years, range 22-61 years) with ES were evaluated, treated, and followed up.

RESULTS

All 36 patients underwent resection in our hospital. Among them, the 2 and 5 years local recurrence rates were 32.0% and 45.1%, respectively, with a better prognosis in patients with R0 resection margin. Distant metastasis rates for the 33 patients with M0 after 2 and 5 years were 51.5% and 70.8%, respectively. Overall survival rates at 2 and 5 years for 36 patients were 74.8% and 43.3%, respectively. Tumor size (>5 cm) and M1 were significantly associated with a poor overall survival. But the R0 resection margin was the only prognostic factor for influencing the LRFS and DMFS.

CONCLUSIONS

The R0 resection margin and small tumor size were critical for a better prognosis.

Case Report: Pulmonary Metastases From Epithelioid Sarcoma in Extremity Favourably Responding to Immunotherapy With Camrelizumab

Epithelioid sarcoma (ES) is a rare soft tissue sarcoma (STS), with limited therapies available for metastatic disease. Here, we describe a case of a 30-year-old male with ES of the left knee and underwent surgery and radiation therapy for the primary disease. After 2 years, he had local recurrence and underwent extensive resection surgery; however, adjuvant chemotherapies were delayed due to recurrent wound infection. Nine months after the second surgery, progressive disease was confirmed after detection of metastases to the lungs and inguinal lymph nodes. Amputation was performed for the local recurrence, followed by inguinal lymph nodes dissection. Pazopanib was transiently administered but discontinued as a result of wound dehiscence. The tumour specimens were detected with unexpected high level of PD-L1 expression and tumoural infiltrating lymphocytes. Subsequently, he received camrelizumab 2.0 mg/kg every 21 days for 18 cycles with rapid remission of the pulmonary metastases. This promising response to camrelizumab indicates that immunotherapies may be an alternative choice for patients with metastatic ES in lung based on analysing the tumour immune microenvironment.

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.

Primary pulmonary epithelioid sarcoma: a case report

Background

Epithelioid sarcoma most frequently occurs in the dermal or subcutaneous area of the distal extremities. To date, there have been three cases of primary pulmonary epithelioid sarcoma reported. We report a case of epithelioid sarcoma that is considered a primary lung tumor.

Case presentation

A 65-year-old asymptomatic Asian male patient underwent chest radiography during a routine health examination, and an abnormal mass was detected. His past medical history was unremarkable. He smoked 40 cigarettes every day and had slightly obstructive impairment on spirometry. He worked as an employee of a company and had no history of asbestos exposure. He underwent partial resection of the right lung by thoracoscopy. A histological examination of the tumor revealed a cellular nodule of epithelioid and spindle-shaped cells. Some of the tumor cells displayed rhabdoid features and reticular arrangement in a myxomatous stroma. Immunohistochemically, the tumor cells were positive for vimentin, smooth muscle actin (SMA), CD34, and epithelial membrane antigen (EMA); loss of the BAF47/INI1 protein in the tumor cells was also confirmed. A diagnosis of epithelioid sarcoma was established. Careful screening by whole-body positron emission tomography for another primary lesion after surgery did not detect any possible lesion. He had no cutaneous disease.

Conclusion

To our knowledge, this is the fourth case of a proximal-type epithelioid sarcoma considered as a primary lung tumor.

Pseudoendocrine Sarcoma: Clinicopathologic Analysis of 23 Cases of a Distinctive Soft Tissue Neoplasm With Metastatic Potential, Recurrent CTNNB1 Mutations, and a Predilection for Truncal Locations

The number of recognized epithelioid soft tissue neoplasms continues to increase and includes epithelioid schwannoma, sclerosing epithelioid fibrosarcoma, and emerging entities such as sarcomas with GLI1 alterations. Here, we describe 23 cases of a previously unrecognized entity, provisionally termed "pseudoendocrine sarcoma." Pseudoendocrine sarcoma is a rare, distinctive tumor of uncertain lineage with a predilection for paravertebral soft tissue in older adults. Fifteen patients (65%) were male and 8 were female. Age at presentation ranged from 29 to 78 years (median: 62 y). Nineteen tumors (83%) occurred in truncal locations, including 15 tumors (65%) in paravertebral soft tissue; other locations included the posterior head (2 tumors), thigh (1), and orbit (1). Tumor size ranged from 2 to 19 cm (median: 6.35 cm). Pseudoendocrine sarcoma is composed of sheets, trabeculae, and nests of epithelioid or ovoid cells with indistinct borders, palely eosinophilic cytoplasm, and highly monomorphic, round nuclei with speckled chromatin. Pseudoglandular architecture was at least focally present in 16 tumors (70%), large extracellular hyaline globules were identified in 12 tumors (52%), and psammomatous calcifications were present in 8 (35%). Metaplastic ossification was identified in 2 tumors, and myxoid stroma was present in 1. Lymphovascular invasion was present in 5 of 18 tumors (28%). Immunohistochemistry demonstrated that most tumors showed nuclear positivity for β-catenin (20/21 tumors; 95%), and some showed at least focal positivity for S-100 (9/22; 41%), desmin (3/8; 38%), or CD34 (2/8; 25%). All tumors were negative for neuroendocrine and epithelial markers, including synaptophysin (21 tumors), chromogranin (19), INSM1 (4), pan-K (16), CAM5.2 (13), AE1/AE3 (6), epithelial membrane antigen (20), and E-cadherin (13). DNA sequencing detected CTNNB1 point mutations in all 6 sequenced tumors: D32H, S33C, S33F, S37A, S37C, and S37F. RNA sequencing was negative for gene fusions in all 6 sequenced tumors. Clinical follow-up was available for 17 patients (74%; range: 4 mo to 20 y; median: 3.5 y), including 14 patients with >1 year of follow-up. Six of 14 patients with long-term follow-up experienced local recurrence (43%, at intervals of 3 to 6 y). One tumor showed a local lymph node metastasis within the primary excision specimen, and 3 patients developed distant lung metastases (21%). No patient died of the disease as yet. Despite its bland morphology and resemblance to the well-differentiated neuroendocrine tumor, pseudoendocrine sarcoma is best considered an intermediate-grade sarcoma, given its pathologic characteristics and clinical behavior.

Extrarenal rhabdoid tumour of the vulva: diagnostic and management challenges

Extrarenal rhabdoid tumour (ERT) of vulva is a rare gynaecological neoplasm with an aggressive course and no clear management guidelines. We present the case of a 25-year-old woman with a rapidly increasing mass in right vulva suggestive of sarcoma. Wide local excision was done. Histopathology examination revealed ERT of vulva. Six weeks later she manifested lung metastases. Despite adjuvant chemotherapy, the disease progressed and she died 8 months later. We review the literature and briefly discuss the epidemiology, treatment approaches, prognostic factors and expected outcomes of this rare disease.

Update on Cutaneous Soft Tissue Tumors

This article focuses on various recently described or emerging cutaneous soft tissue neoplasms. These entities encompass a wide range of clinical and histologic characteristics. Emphasis is placed on their distinguishing morphologic and immunophenotypic features compared with entities that enter into their differential diagnosis, as well as novel immunophenotypic and molecular tests that are often necessary for accurate diagnosis of these entities. Entities discussed include EWSR1-SMAD3-rearranged fibroblastic tumor, superficial CD34-positive fibroblastic tumor, epithelioid fibrous histiocytoma, CIC-rearranged sarcomas, and NTRK-rearranged spindle cell tumors.

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.

Epithelioid Sarcoma of the Peripheral Nerve: Clinicopathologic Series of Three Cases and Literature Review

OBJECTIVES

Epithelioid sarcoma (ES) rarely arises in the nerve. To increase our understanding of this unusual tumor originating in the nerve, we describe the features of three cases and review the literature.

METHODS

Clinical data, imaging, pathology, treatment, and follow-up are detailed. A systematic literature review was conducted.

RESULTS

Two patients were male and one female; the median age was 24 years. The patients had neurologic symptoms, and the tumors arose in large nerves and ranged from 2.4 to 5.8 cm. The tumors were avid on positron emission tomography-computed tomography and showed increased signal intensity on T2-weighted magnetic resonance imaging. Centered in the nerve, the tumors grew with an infiltrative pattern and encased the nerve fascicles. All were treated with wide resection, and adjuvant treatment included combinations of chemotherapy and radiation. One recurred, and the limb was amputated. Metastases were documented to lymph nodes, lung, pleura, and skin. One patient died of disease after 54 months. Literature review including our cases showed that tumors stained with pancytokeratin (9/9), EMA (4/4), and CD34 (7/7); there was loss of INI1 in all six cases tested.

CONCLUSIONS

ES rarely arises in the peripheral nerve, and its infiltrative nature often requires morbid surgery. The differential includes a variety of benign and malignant epithelioid neoplasms.

Epithelioid Sarcoma Presenting as Non-Healing Traumatic Ulcer: A Case Report and Review of the Literature

Epithelioid sarcoma is a rare soft tissue sarcoma. It is a slow-growing neoplasm, which usually presents as a painless mass in the extremities and typically grows along deep dermal and subcutaneous planes. In contrast to other types of sarcoma, it has a strong tendency for nodal metastasis and local metastasis adjacent to the primary lesion within the affected limb. 

In this article, we present a case of chronic traumatic ulcer in the upper extremity in an adolescent male that was subsequently diagnosed as epithelioid sarcoma, which is a very unusual mode of presentation of this particular tumour. The patient was treated with wide local excision and reconstruction with a free flap. Histopathological examination and immunochemistry studies confirmed the diagnosis and the patient underwent radiotherapy post-operatively as a part of the treatment regime. His post-treatment period was unremarkable, and he was put on regular surveillance to monitor the development of any signs of disease recurrence. Patients with epithelioid sarcomas often present late due to the slow-growing nature of the tumour. Unusual presentations like this will further delay the diagnosis and treatment, which will eventually worsen the prognosis. Awareness of such presentations can encourage primary care physicians to make early referrals to experts, which, in turn, may help the patients get early treatment and have a better prognosis.

Proceedings of the North American Society of Head and Neck Pathology, Baltimore, MD, March 17, 2021: The Mistakes I Made When I Stepped Out of My Neck of the Woods

Rapidly growing, symptomatic, non-hematological, malignant neck masses are unusual in young adults. We report a case of a 34-year-old African American male with sickle cell trait who presented with a large left supraclavicular/cervical mass comprising of poorly differentiated malignant epithelial cells consistent with metastatic carcinoma of unknown origin. Upon immunohistochemistry, the tumor showed loss of INI1 (BAF47) and retained PAX-8 expression. After extensive clinical and radiological work-up the primary tumor was found to be a 2.6 cm renal medullary carcinoma. This case highlights the role of multidisciplinary approach to the diagnosis of a neck mass and to understanding that certain genetically-defined tumors can occur at and metastasize to any site.

Epithelioid sarcoma: A clinicopathological study of 12 head and neck cases

OBJECTIVES

To determine the clinicopathological features of epithelioid sarcoma presenting in head and neck region (HNES) and elucidate diagnostic key points and treatment options for HNES.

MATERIALS AND METHODS

A total of 12 HNES cases were collected in our department from 2010 to 2020. Their clinical information and pathological features were documented, and relevant follow-up was performed. Immunohistochemistry was carried to analyze the protein markers of HNES.

RESULTS

Of the 12 HNES cases, 10 were primary tumors and 2 were metastasized from foot and shoulder, respectively. The patients with primary tumors were significantly younger than those with metastasized ones (22.7 vs 41.5, p = .0157), and male patients outnumbered female patients (3:1). Of all HNES cases, 9 were classic subtype, and 3 were proximal subtype. HNES patients had a poor prognosis, with 5-year overall survival of 41.5% and 5-year relapse-free survival of 22.5%. A loss of INI1 was identified as the hallmark of HNES with 83.3% (10/12) of HNES cases presenting as EZH2 positive.

CONCLUSIONS

HNES is more prevalent at younger ages and in males, has a poor prognosis, and exhibits a greater proportion of classic subtype than proximal subtype. EZH2 inhibitor has therapeutic potential in HNES.

Epithelioid Sarcoma of Lumbar Spine: A Rare Mesenchymal Tumor Masquerading as Infection

Epithelioid sarcoma of the spine has been rarely reported in the literature. Its diagnosis is challenging due to nonspecific findings. We report a case of 42-year-old gentleman with back pain. Magnetic resonance imaging (MRI) revealed lesion in the L4 vertebral body extending into the spinal canal with pre and paravertebral involvement. He underwent posterior spinal decompression and instrumentation with biopsy. Histopathological examination was nonspecific. Considering clinical and radiological features, antitubercular treatment was initiated. The patient developed acute onset weakness of both lower extremities 1 month post-surgery. Repeat MRI and positron emission tomography (PET) computed tomography revealed an increase in the extent of lesion which required revision decompression. Histopathological examination showed cells with epithelioid appearance, positive for Vimentin, and epitheloid membrane antigen in immunohistochemistry. Radiotherapy was planned but the patient expired due to multiorgan dysfunction. Epithelioid sarcomas are rare soft-tissue neoplasms with poor prognosis. They can mimic infection and a high degree of suspicion is required in these cases to diagnose and treat them early.

Management of sarcomas in children, adolescents and adults: Interactions in two different age groups under the umbrellas of GSF-GETO and SFCE, with the support of the NETSARC+ network

Sarcomas are a rare heterogeneous group of malignant neoplasms that can arise in almost any anatomic site and any age. Close collaboration among adult and pediatric cancer specialists in the management of these tumors is of foremost importance. In this review, we present the current multidisciplinary organization in care of patients with sarcoma in France and we review the main advances made in the last decades in systemic and radiotherapy treatment in the main sarcoma types diagnosed in children, adolescents and young adults (AYA), thanks to the international collaboration.

Early clinical and metabolic response to tazemetostat in advanced relapsed INI1 negative epithelioid sarcoma

Epithelioid sarcoma (ES) is a rare soft tissue sarcoma with an incidence of 0.05 per 100,000 population in the USA. It is characterized by multiple local recurrences and regional lymph nodes form the commonest site of metastases. The function of Integrase Inhibitor 1 (INI1) protein is lost in more than 90% of cases, which was the basis for the introduction of tazemetostat into the therapeutic armamentarium for management of advanced ES. The efficacy and manageable toxicity profile of tazemetostat have been demonstrated recently, leading to its accelerated approval for treatment of advanced ES. We report one of the first real-world cases of relapsed, metastatic ES treated with tazemetostat. The patient attained partial response with the therapy and is tolerating the drug well without serious toxicities.

Epithelioid Sarcoma of the External Auditory Canal: An Uncommon Tumor at an Unusual Site and a Brief Overview of the Literature

We present a case (41 years old pregnant female) with epithelioid sarcoma arising in the left external auditory canal. On immunohistochemistry, the tumor cell diffusely expressed cytokeratins and showed patchy expression of ERG and CD34. The neoplastic cells demonstrated uniform loss of INI1-expression. Epithelioid sarcoma arising in the external auditory canal is rare. Awareness that ES may rarely arise at unusual sites is of critical importance in order to apply a broad enough panel in the immunohistochemical study, so a misdiagnosis of carcinoma can be avoided.

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.

Malignant Epithelioid Soft Tissue Tumours- A Pathologist's Perspective With Review of Literature

Background Soft tissue tumours with epithelioid morphology have many differential diagnoses, which include epithelioid sarcoma, malignant extrarenal rhabdoid tumour, epithelioid malignant peripheral nerve sheath tumour, epithelioid leiomyosarcoma, epithelioid angiosarcoma and sclerosing epithelioid fibrosarcoma. There are other rare entities also. They often express characteristic patterns of immunohistochemical markers that can be used to identify these tumours. Materials and methods This retrospective study comprises 22 cases of malignant soft tissue tumours with epithelioid differentiation diagnosed over a period of four years. Findings regarding clinical presentation, cytological findings, histopathological findings and immunohistochemical profile of the tumours were noted and analyzed. Results A total of 22 cases were included in the study including five cases of epithelioid sarcoma (conventional and proximal), three cases of epithelioid angiosarcoma and epithelioid myxofibrosarcoma, two cases of epithelioid malignant peripheral nerve sheath tumour, epithelioid gastrointestinal stromal tumour and clear cell sarcoma each, one case of epithelioid leiomyosarcoma, sclerosing epithelioid fibrosarcoma, malignant extrarenal rhabdoid tumour, monophasic synovial sarcoma and malignant and malignant perivascular epithelioid cell tumour each. Conclusion Pathologists should be aware of the various differential diagnoses of soft tissue tumours with epithelioid morphology. Over and above the clinical findings and morphological features, ancillary methods like immunohistochemistry help to arrive at a definitive diagnosis in most cases.

Update on SWI/SNF-related gynecologic mesenchymal neoplasms: SMARCA4-deficient uterine sarcoma and SMARCB1-deficient vulvar neoplasms

Our knowledge regarding the role of genes encoding the chromatin remodeling switch/sucrose non-fermenting (SWI/SNF) complex in the initiation and progression of gynecologic malignancies continues to evolve. This review focuses on gynecologic tumors in which the sole or primary genetic alteration is in SMARCA4 or SMARCB1, two members of the SWI/SNF chromatin remodeling complex. In this review, we present a brief overview of the classical example of such tumors, ovarian small cell carcinoma of hypercalcemic type, and then a detailed review and update of SMARCB1-deficient and SMARCA4-deficient tumors of the uterus and vulva.

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.

Undifferentiated and dedifferentiated neoplasms of the female genital tract

Undifferentiated neoplasms in the female gynecologic tract comprise two main groups-undifferentiated carcinoma, most common in the endometrium and ovary, and undifferentiated uterine sarcoma, although tumors with an undifferentiated appearance may occur in all gynecologic organs. Their differential diagnosis is broad and generous sampling, careful morphological evaluation, judicious use of immunohistochemistry, and in many cases, molecular testing is often essential in the diagnostic work-up. As some of these neoplasms fail to respond to conventional chemotherapy regimens and/or radiation therapy, targeted therapy may be valuable in treating these highly aggressive tumors, thus the importance of precise diagnosis. In this review we discuss the clinicopathological features of undifferentiated carcinoma, dedifferentiated carcinoma, and undifferentiated uterine sarcoma, followed by a comprehensive analysis of morphological mimickers. Finally, we briefly review ovarian and lower genital tract tumors with an undifferentiated histological appearance.

Epithelioid sarcoma of the hand: a wolf in sheep's clothing

Epithelioid sarcoma (ES) of the hand is a rare, aggressive cutaneous malignancy with high rates of recurrence, metastases and mortality. With an incidence rate of 0.4 cases/y per one million population, which compromise for approximately 1-1.4% of all soft tissue sarcoma, ES accounts for 10% of soft tissues sarcomas of the hand and foot. Its aggressiveness and propensity to spread and metastases without being noticed, makes it unique and potentially lethal. Missed or delayed diagnosis are often encountered as this tumor can mimic variety of different entities and due to the infrequent nature of this lesion, treatment options are still controversial. The authors provide systemic review of the current literature on epidemiology, etiology, pathogenesis, management and outcomes of this disease as well as a case presentation and a proposed treatment algorithm. The choice of treatment option depends on disease characteristics, staging at presentation, regional lymph node involvement, comorbidities and performance status of the patient. Emphasis on a multidisciplinary coordinated care is crucial as early diagnosis and treatment can decrease morbidity and mortality rates.

The epigenomics of sarcoma

Epigenetic regulation is critical to physiological control of development, cell fate, cell proliferation, genomic integrity and, fundamentally, transcriptional regulation. This epigenetic control occurs at multiple levels including through DNA methylation, histone modification, nucleosome remodelling and modulation of the 3D chromatin structure. Alterations in genes that encode chromatin regulators are common among mesenchymal neoplasms, a collection of more than 160 tumour types including over 60 malignant variants (sarcomas) that have unique and varied genetic, biological and clinical characteristics. Herein, we review those sarcomas in which chromatin pathway alterations drive disease biology. Specifically, we emphasize examples of dysregulation of each level of epigenetic control though mechanisms that include alterations in metabolic enzymes that regulate DNA methylation and histone post-translational modifications, mutations in histone genes, subunit loss or fusions in chromatin remodelling and modifying complexes, and disruption of higher-order chromatin structure. Epigenetic mechanisms of tumorigenesis have been implicated in mesenchymal tumours ranging from chondroblastoma and giant cell tumour of bone to chondrosarcoma, malignant peripheral nerve sheath tumour, synovial sarcoma, epithelioid sarcoma and Ewing sarcoma - all diseases that present in a younger patient population than most cancers. Finally, we review current and potential future approaches for the development of sarcoma therapies based on this emerging understanding of chromatin dysregulation.