Successful surgical resection of a metastatic clear cell sarcoma in the heart: a case report

Background

Clear cell sarcoma (CCS) is a very rare disease and one with a very poor prognosis. Furthermore, its occurrence in the heart is very rare and past reports are scarce.

Case summary

A 33-year-old man who had undergone left arm amputation due to CCS came to the hospital because a positron emission tomography computed tomography (PET-CT) four years post-amputation showed an accumulation in the heart. The PET-CT with glucose suppression treatment showed fluorodeoxyglucose accumulation in the myocardium between the middle of the anterolateral wall and the papillary muscle of the posterior lateral wall of the left ventricle (LV). Based on the course of the disease up to now, it was considered that the accumulation was most likely metastasis of CCS. Observation of the heart after a median sternotomy revealed a white tone, well-defined lesion in the middle of the anterolateral wall of LV. The tumour on the posterolateral side of LV was not exposed on the surface, but it was palpated and was still recognizable as a firm neoplastic lesion. Because the mass was identified as a sarcoma on intraoperative rapid pathology, we decide to perform a total resection. Both lesions were excised, and pathology revealed a diagnosis of CCS.

Discussion

Clear cell sarcoma is a very rare disease that accounts for <1% of all soft tissue sarcomas, and its occurrence in the heart is even rarer. It requires a combination of many imaging modalities. To our knowledge, this is the first case of CCS in the heart treated with surgical resection.

A Comparison of Clear Cell Sarcoma to Jaw and Salivary Tumors Bearing EWS Fusions

OBJECTIVE

To review tumors identified as "clear cell sarcoma" in order to determine similarities to the rare EWS fusion positive jaw and salivary gland tumors clear cell odontogenic carcinoma (CCOC) and clear cell carcinoma of the salivary gland (CCC).

METHODS

PubMed was used to collect all reports of clear cell sarcoma (CCS). Search parameters were "clear cell sarcoma" and "CCS." References in the publications were screened and cross-referenced. Data extracted included demographic characteristics, presenting signs and symptoms, radiographic findings, histological and immunohistochemical features and known molecular/genetic aberrations.

RESULTS

Clear cell sarcoma has several similarities to CCOC and CCC. All three tumor types have similar histologic appearances including the presence of clear cells, as well as similar genetic profiles in that all harbor an EWSR1-CREB family fusions. Additionally, these tumors appear in soft tissue as well as bone, and can have a prolonged clinical course. CCS can appear anywhere in the body, including the head and neck region. All three tumors appear to have a predilection to women, although CCS may have a slight younger age of onset as compared to CCOC and CCC (3rd vs 5th decade of life, respectively).

CONCLUSION

Gaining a better understanding of the similarities and differences between these three tumors may lead to a better understanding of each one.

Metastatic clear cell sarcoma of the pancreas: A rare case report

BACKGROUND

Clear cell sarcoma (CCS) is a rare soft-tissue sarcoma. The most common metastatic sites for CCS are the lungs, bones and brain. CCS is highly invasive and mainly metastasizes to the lung, followed by the bone and brain; however, pancreatic metastasis is relatively rare.

CASE SUMMARY

We report on a rare case of CCS with pancreatic metastasis in a 47-year-old man. The patient had a relevant medical history 3 years ago, with abdominal pain as the main clinical manifestation. No abnormalities were observed on physical examination and the tumor was found on abdominal computed tomography. Based on the medical history and postoperative pathology, the patient was diagnosed with CCS with pancreatic metastasis. The patient was successfully treated with surgical interventions, including distal pancreatectomy and splenectomy.

CONCLUSION

This report summarizes the available treatment modalities for CCS and the importance of regular postoperative follow-up for patients with CCS.

Clear cell sarcoma in the post-molar area: Report of an ultra-rare case and literature review of oral clear cell sarcoma

BACKGROUND

Clear cell sarcoma of soft tissue is an exceptionally rare sarcoma. It is even rarer in the oral cavity. To our knowledge, this case is the first reported clear cell sarcoma involving the post-molar area. Pathologically, clear cell sarcoma has low mitotic activity, rare nuclear pleomorphism, and necrosis. Its biological behavior is often underestimated by morphology. It is a highly aggressive tumor.

CASE REPORT

A 39-year-old female presented with an asymptomatic mass in the post-molar area. It was mistaken for a benign or low-grade malignant tumor based on frozen incisional biopsy samples. The surgical resection sample was tested by NGS, which detected a rare EWSR1::CREB1 in clear cell sarcoma. The final diagnosis was made by combining morphological, immunohistochemical, and molecular test results. The patient did not receive any adjuvant therapy after surgery and no recurrence of the disease was detected at 8 months of follow-up.

CONCLUSION

The study highlights that mild histological manifestation in the oral cavity should be considered the possibility of CCS affecting young patients. Careful histological investigation, sufficient immunohistochemical staining, and molecular tests are essential to the diagnosis.

Melanin-targeted [18F]-PFPN PET imaging may shed light for clear cell sarcoma

PURPOSE

Intracytoplasmic melanin pigment is a characteristic of clear cell sarcoma (CCS), which is a particularly deadly type of soft-tissue sarcoma. [18F]-N-(2-(diethylamino)ethyl)-5-(2-(2-(2-fluoroethoxy)ethoxy)ethoxy)picolinamide ([18F]-PFPN) is a positron emission tomography (PET) probe characterized by high melanin affinity. Therefore, this study aimed to investigate the feasibility of melanin-targeted [18F]-PFPN PET in patients with CCS.

METHODS

This prospective single-centre study recruited patients with pathologically confirmed CCS. [18F]-FDG PET/computed tomography and [18F]-PFPN PET/magnetic resonance imaging scans were performed within 1 week of each other. The lesion numbers and [18F]-FDG and [18F]-PFPN PET parameters (maximum standardized uptake value [SUVmax], mean standardized uptake value [SUVmean], metabolic/melanotic tumour volume [MTV/MLTV], and total lesion glycolysis/melanin [TLG/TLM]) were collected.

RESULTS

Three patients with CCS were recruited and received PET imaging. A total of 56 lesions were detected on [18F]-PFPN PET, including primary tumour and distant metastases. Identical lesions were not detected on [18F]-PFPN and [18F]-FDG PET. Twelve lesions (12/39, 30.77%) on [18F]-FDG imaging were missed on [18F]-PFPN, and 20 lesions (20/47, 42.55%) on [18F]-PFPN imaging were missed on [18F]-FDG. In quantitative analysis, the [18F]-FDG SUVmean (4.60 ± 3.24) was higher than the [18F]-PFPN SUVmean (3.0 ± 2.63) in all lesions (P = 0.01). No significant correlations were found between the SUVmax, SUVmean, MLTV/MTV, and TLM/TLG values of [18F]-PFPN and [18F]-FDG (P > 0.05).

CONCLUSION

Melanin-targeted [18F]-PFPN PET imaging is feasible for the diagnosis of CCS. Different imaging features were displayed on [18F]-PFPN and [18F]-FDG PET imaging, demonstrating the complementary role of the tracers. Combined use of the two imaging modalities would be preferred in patients with CCS.

CLINICAL TRIAL REGISTRATION

NCT05963035.

A cystic non-Wilms renal tumor in a Nepalese boy: A rare case of clear cell sarcoma

INTRODUCTION

Clear cell sarcoma of the kidney (CCSK) is an uncommon childhood malignancy known for its aggressive behavior and tendency to recur and metastasize to the brain and bones.

CASE PRESENTATION

We report a four-year-old boy evaluated for non-specific abdominal pain with an incidental radiological finding of a right lower pole cystic renal mass initially thought to be cystic Wilms' tumor. A pretherapy core biopsy of the mass suggested a clear cell tumor. An open transperitoneal radical nephroureterectomy with aortocaval lymph node sampling was done. Based on histopathological findings and immunohistochemical analysis, CCSK was diagnosed. Appropriate chemotherapy and radiotherapy were instituted postoperatively. At six years follow-up, he was tumor-free and doing well.

CLINICAL DISCUSSION

The workup for CCSK includes diagnostic and metastatic imaging, histopathology, and immunohistochemistry analysis. Diagnostic segregation of CCSK and Wilms' tumor is imperative to institute optimal oncological management and improve overall treatment outcomes.

CONCLUSION

Considering the age of presentation and clinico-radiological appearance, CCSK can be mistaken for Wilms' tumor, which is much more common in occurrence despite the distinguishable histopathological features, treatment modalities, and prognosis.

Clear cell sarcoma: state-of-the art and perspectives

INTRODUCTION

Clear cell sarcoma (CCS) is an ultrarare soft tissue sarcoma (STS) with a poor prognosis due to its propensity to metastasize and its low chemosensitivity. The standard treatment of localized CCS consists of wide surgical excision with or without additive radiotherapy. However, unresectable CCS is generally treated with conventional systemic therapies available for treatment of STS despite the weak scientific evidence to support its use.

AREAS COVERED

In this review, we discuss the clinicopathologic characteristics of CSS, as well as the current treatment landscape and future therapeutic approaches.

EXPERT OPINION

The current treatment strategy of advanced CCSs, based on STSs regimens, shows a lack of effective options. Combination therapiesin particular, the association of immunotherapy and TKIs, represent a promising approach. Translational studies are needed in order to decipher the regulatory mechanisms involved in the oncogenesis of this ultrarare sarcoma and identify potential molecular targets.

Targeting epigenetic features in clear cell sarcomas based on patient-derived cell lines

BACKGROUND

Clear cell sarcomas (CCSs) are translocated aggressive malignancies, most commonly affecting young adults with a high incidence of metastases and a poor prognosis. Research into the disease is more feasible when adequate models are available. By establishing CCS cell lines from a primary and metastatic lesion and isolating healthy fibroblasts from the same patient, the in vivo process is accurately reflected and aspects of clinical multistep carcinogenesis recapitulated.

METHODS

Isolated tumor cells and normal healthy skin fibroblasts from the same patient were compared in terms of growth behavior and morphological characteristics using light and electron microscopy. Tumorigenicity potential was determined by soft agar colony formation assay and in vivo xenograft applications. While genetic differences between the two lineages were examined by copy number alternation profiles, nuclear magnetic resonance spectroscopy determined arginine methylation as epigenetic features. Potential anti-tumor effects of a protein arginine N-methyltransferase type I (PRMT1) inhibitor were elicited in 2D and 3D cell culture experiments using cell viability and apoptosis assays. Statistical significance was calculated by one-way ANOVA and unpaired t-test.

RESULTS

The two established CCS cell lines named MUG Lucifer prim and MUG Lucifer met showed differences in morphology, genetic and epigenetic data, reflecting the respective original tissue. The detailed cell line characterization especially in regards to the epigenetic domain allows investigation of new innovative therapies. Based on the epigenetic data, a PRMT1 inhibitor was used to demonstrate the targeted antitumor effect; normal tissue cells isolated and immortalized from the same patient were not affected with the IC50 used.

CONCLUSIONS

MUG Lucifer prim, MUG Lucifer met and isolated and immortalized fibroblasts from the same patient represent an ideal in vitro model to explore the biology of CCS. Based on this cell culture model, novel therapies could be tested in the form of PRMT1 inhibitors, which drive tumor cells into apoptosis, but show no effect on fibroblasts, further supporting their potential as promising treatment options in the combat against CCS. The data substantiate the importance of tailored therapies in the advanced metastatic stage of CCS.

Beyond Wilms tumor: imaging findings and outcomes of rare renal tumors in children

BACKGROUND

Compared to Wilms, non-Wilms renal tumors in children are less well understood due to their rare occurrence which limits precise definition of the typical imaging patterns.

OBJECTIVE

This study aims to identify distinctive imaging findings, demographic characteristics and prognosis of pediatric non-Wilms renal tumors.

MATERIALS AND METHODS

From January 2007 to December 2018, 207 patients with a diagnosis of primary kidney neoplasia were yielded from our radiology archive, 171 of whom were diagnosed with Wilms tumor, 4 with angiomyolipoma and one with nephrogenic rest. The remaining 31 patients with a diagnosis of primary kidney neoplasia were enrolled in this retrospective study. Imaging data, age, gender, prognosis and findings regarding follow-up were noted.

RESULTS

Eight patients had renal cell carcinoma, seven had clear cell sarcoma, six had mesoblastic nephroma, four had rhabdoid tumor, three had desmoplastic small round cell tumor, two had cystic nephroma and one had metanephric stromal tumor. The age of diagnosis was > 8 years for renal cell carcinoma and desmoplastic small round cell tumor, < 5 years for rhabdoid tumor and < 7 months for mesoblastic nephroma. There was no gender preference for any tumor type. The prognosis for rhabdoid tumor was extremely poor in that all the patients followed up in our institute were deceased, whereas no recurrence was found in other tumors. Translocation type renal cell carcinoma had lower T2-weighted signal intensity, mesoblastic nephroma was a predominantly cystic mass, clear cell sarcoma was generally larger at presentation and extensive amorphous calcifications were seen in desmoplastic small round cell tumor.

CONCLUSION

For the differential diagnosis of pediatric non-Wilms renal tumors, age is the most important factor, followed by propensity to metastasize/aggressive behavior of the mass. Knowledge of specific imaging findings of these tumors may help to narrow the differential diagnosis.

Primary clear cell sarcoma of soft tissue in the posterior cervical spine invading the medulla oblongata: A case report

BACKGROUND

Clear cell sarcoma (CCS) is a rare and highly malignant soft tissue tumor, usually occurring in the deep soft tissues of the distal tendons and aponeurosis of the extremities, especially the feet and knees. CCS originating in the head and neck is extremely rare. The clinical manifestations of CCS in the head and neck are not typical, and the imaging manifestations have certain characteristics, but the diagnosis still depends on pathological examination and genetic testing.

CASE SUMMARY

A 33-year-old male patient had paroxysmal headache for more than 4 years, accompanied by nausea and vomiting, which could be relieved after rest. Computed tomography angiography showed a left paraspinal soft tissue mass. Contrast-enhanced imaging showed obvious uneven enhancement with adjacent bone lytic destruction. Magnetic resonance imaging examination showed isosignal on T₁-weighted images, slightly high signal on T₂-weighted images (T₂WI), high signal on Tirm fat suppression sequence, significantly high signal on diffusion weighted imaging, and obvious and uneven enhancement. The lesion invaded the anterior medulla oblongata through the left atlantoaxial foramen and compressed the cervical spinal cord on T₂WI. Primary CCS of soft tissue was diagnosed by pathology and genetic examination.

CONCLUSION

CCS should be considered in the differential diagnosis of soft tissue tumors of the head and neck, and their diagnosis depends on pathological examination and genetic testing.

Malignant gastrointestinal neuroectodermal tumor in head and neck: two challenging cases with diverse morphology and different considerations for differential diagnosis

Malignant gastrointestinal neuroectodermal tumor (MGNET) is a sarcoma typically involving the gastrointestinal tract with neuroectodermal differentiation and EWSR1-ATF1/CREB1 fusions. Recently, rare MGNET cases were reported in extragastrointestinal sites. We identified 2 cases of MGNET arising in unprecedented laryngeal and intracranial locations, respectively. Both cases showed spindle and epithelioid tumor cells with amphophilic to clear cytoplasm and occasionally prominent nucleoli, arranged in solid, fascicular, and pseudoalveolar patterns. Case 1 exhibited moderate to marked nuclear atypia and focal intraepithelial component. In contrast, case 2 comprised predominantly low-grade epithelioid cells with extensive pseudopapillary structures. Both tumors showed an S100/SOX10-positive and HMB45/melan-A-negative immunoprofile as well as EWSR1-ATF1 fusion. A chief obstacle in diagnosing case 1 was the histologic and immunophenotypic resemblance to melanoma. The striking pseudopapillary architecture and the intracranial location of case 2 rendered differential diagnoses including meningioma and ependymoma. With the peculiar locations and morphology, these cases posed great diagnostic challenge.

Primary Clear Cell Sarcoma of the Lung: a Case Report

Background:

Clear Cell Sarcoma of Soft Tissue (CCSST), or melanoma of the soft part, is a rare, aggressive tumor that originates in the aponeurosis and fasciae of the distal parts of the extremities. Reports from other sites of the body are rare.

Objective:

We are reporting an extremely rare tumor that presented as a central left-sided lung mass and found to be clear cell sarcoma of soft tissue.

Methods:

We report a 24-year-old male patient presented with recurrent attacks of left-sided chest pain associated with cough and dyspnea.

Results:

Imaging showed a central left-sided 8*5.5*5 cm lung mass. The age of the patient and the radiological characteristics of the lesion were suggestive of a benign pathology. After histopathological assessment of the lesion, suspicion of the malignant process was raised, mainly melanoma of soft part and PEComa. The patient underwent left-sided pneumonectomy. The postoperative histological examination, immunohistochemical findings including positive staining for S-100, HMB-45, and Melan-A, and positive FISH study for EWSR1 gene rearrangements supported the diagnosis of CCSST originating primarily in the major fissure of left the lung.

Conclusion:

The rarity of CCSST in general and tumors originating in the lung primarily raise the challenges in hypothesizing a differential diagnosis, choosing proper investigations and treatment methods. The histological examination, immunohistochemical, and cytogenetics of the tumor are mandatory to reach the final diagnosis.

Retrospective analysis of outcomes in patients with clear cell sarcoma of the kidney: A tertiary single-institution experience

BACKGROUND

Clear cell sarcoma of the kidney (CCSK) is a rare and aggressive tumor. This study aims to describe the clinical characteristics and outcomes of CCSK patients in one of the largest pediatric medical centers in China.

METHODS

We included all patients diagnosed with CCSK between January 2008 and March 2019 at the Children's Hospital of Chongqing Medical University, China. The patients' demographics, clinical presentation, and management were reviewed. Follow-up was continued until December 2019.

RESULTS

In total, 41 CCSK patients (66% male) with a median age of 24 months (range 3-108 months) were identified. The stage distributions of stages I, II, III and IV were 42%, 34%, 24% and 0%, respectively. Preoperative chemotherapy was administered to 7/41 patients. All patients underwent radical nephrectomy and postoperative chemotherapy. The median number of lymph nodes sampled was 4 (range 1-12). Radiotherapy was applied in 8/41 patients. The 5-year event-free survival (EFS) and overall survival (OS) were 63.9% and 78.8%, respectively. Of the 41 patients, 11 patients experienced relapse at a median time of 19 months (range 5-72 months). The most common site of recurrence was the tumor bed (9/11). Young age was a significant adverse prognostic factor for EFS.

CONCLUSIONS

The overall outcome of CCSK patients in our hospital is poorer than that in developed regions. More research is needed to clarify the underlying causes of poorer outcomes in young patients and improve outcomes.

TYPE OF STUDY

Retrospective study.

LEVEL OF EVIDENCE

LEVEL IV.

Primary clear cell sarcoma of the femur: a unique case with RT-PCR and direct sequencing confirmation of EWSR1/ATF1 fusion gene

Background

It is very rare for clear cell sarcomas (CCS) to arise in the bone. During diagnosis, it is important to distinguish primary CCS of bone from bone metastasis of melanoma because this difference fundamentally changes the therapeutic options. Recently, characteristic fusion genes of CCS have been detected using reverse transcription polymerase chain reaction (RT-PCR) or direct sequencing which allowed to distinguish CCS from melanoma. However, there was no study applying these analyses with positive results. In this case, we describe the use of fusion gene analysis to diagnose a primary CCS of the bone.

Case presentation

A 36-year-old male presented with a four-months history of left knee pain. Magnetic resonance imaging showed a lesion in the left femoral medial epicondyle. Histological examination of the biopsy specimen revealed proliferating oval or rounded cells. These cells had clear cytoplasm arranged in fascicles or compact nests with frequent deposits of brown pigment. Furthermore, immunohistochemistry analysis revealed that tumor cells were positive for S-100 protein, HMB-45, Melan-A, and SOX10. It stained negative for CD34 and BRAF v600e. Conclusively, detection of the EWSR1/ATF1 fusion gene using RT-PCR and direct sequencing confirmed that the lesion was a primary CCS of the bone. Wide-margin resection and reconstruction with a tumor endoprosthesis were performed.

Conclusions

Herein, we diagnosed a rare case of primary CCS of the bone by detecting EWSR1/ATF1 fusion gene using RT-PCR and direct sequencing. Since fluorescence-in situ hybridization (FISH) and RT-PCR could show false positive by mainly due to technical problems, it is better to perform direct sequencing to confidently diagnose the tumor as a primary CCS especially at very rare site such as bone.

Clear cell tumor with melanocytic differentiation and MITF-CREM translocation: a novel entity similar to clear cell sarcoma

The presence of melanocytic differentiation in tumors of non-melanocyte origin is uncommon and is typically associated with the overexpression of MITF, the master regulator of melanin synthesis, or another member of the MIT/TFE3 family. In clear cell sarcoma, the presence of either an EWSR1-ATF1 or EWSR1-CREB1 translocation-derived fusion protein is thought to drive melanocytic differentiation by directly stimulating the expression of MITF. Here, we describe a clear cell neoplasm with melanocytic differentiation that is characterized by a novel MITF-CREM gene fusion. CREM is the third member of the ATF1/CREB1/CREM family, and the nature of the MITF-CREM fusion appears analogous to the EWSR1-ATF1 and EWSR1-CREB1 fusions. Thus, this MITF-CREM-rearranged clear cell tumor represents a novel entity with morphologic, immunohistochemical, and molecular similarity to clear cell sarcoma.

Efficacy of Gemcitabine-based Chemotherapy in Clear Cell Sarcoma of Soft Tissue

BACKGROUND/AIM

Clear cell sarcoma (CCS) is an aggressive sarcoma subtype, resistant to conventional anthracycline-based chemotherapy and radiation. The diagnosis is often challenging due to similarities with malignant melanoma.

PATIENTS AND METHODS

We aimed to analyse the activity of gemcitabine-based chemotherapy in a cohort of patients with CCS treated at the Royal Marsden Hospital.

RESULTS

Five patients with metastatic CCS received gemcitabine as first- or second-line systemic therapy. The median time-to-progression was 10 weeks. The median number of cycles of gemcitabine-based therapy was 3 (range=2-7 cycles). Median overall survival in our cohort was 66 months from the initial diagnosis but in the metastatic setting, the overall survival was reduced to 28 months.

CONCLUSION

Gemcitabine-based therapy has modest activity in CCS. There remains a significant unmet medical need for novel, effective therapies for this disease.

Clear cell sarcoma-like/malignant gastrointestinal neuroectodermal tumor of the tongue: a clinicopathologic and molecular case report

Malignant gastrointestinal neuroectodermal tumor (M-GNET) and clear cell sarcoma (CCS) of soft tissue represent closely related, extremely rare, malignant mesenchymal neoplasm of uncertain differentiation. Both entities are characterized genetically by the same molecular alterations represented by the presence of EWSR1-ATF1 and, more rarely, EWSR1-CREB1 fusion genes. The latter translocation seems to be more represented in M-GNET that, despite significant morphologic overlap with CCS, tends to lack overt features of melanocytic differentiation. Most M-GNET occur in the lower gastrointestinal tract, whereas occurrence in the upper tract has been reported only exceptionally. The differential diagnosis represents a major challenge, and accurate diagnosis impact significantly on therapeutic planning. We herein report the clinicopathologic features of a molecularly confirmed M-GNET that arose at the base of the tongue and review the pertinent literature.

Fine Needle Aspiration Cytology of Malignant Digestive System Gastrointestinal Neuroectodermal Tumor in a Lymph Node Metastasis from a Previously Diagnosed Liver Primary: A Case Report and Review of Literature

Malignant gastrointestinal neuroectodermal tumor (GNET) is an extremely rare neoplasm. Immunohistochemically, GNET typically demonstrates neural differentiation but lacks melanocytic differentiation, making it distinct from clear cell sarcoma of the soft tissues (CCS). Herein we report for the first time the cytomorphologic features of lymph node metastasis from presumably liver GNET. A 36-year-old female presented with fevers, night sweats, loss of appetite, and a 20-lbs weight loss. Radiographic imaging showed a 13 cm heterogeneously enhancing mass in the right lobe of the liver and a hypermetabolic 0.9 cm periportal lymph node on positron emission tomography-computed tomography (PET/CT). Initially, a CT-guided liver biopsy was performed followed by right hepatic lobectomy and portal lymphadenectomy. The liver biopsy and resection showed an S100-protein and SOX10 positive malignant neoplasm and genomic profiling of liver biopsy revealed EWSR1-CREB1gene rearrangement. These findings in conjunction with the morphologic and immunohistochemical profile were diagnostic of GNET. Two months later, she presented with recurrent lymphadenopathy in the upper abdomen. Fine needle aspiration of the periportal nodal mass revealed single and clusters of primitive, large to medium-sized neoplastic cells with round to oval nuclei, high nuclear-cytoplasmic ratio, vesicular chromatin, and prominent nucleoli. The tumor cells were S100 protein and SOX10 positive, consistent with metastasis of the patient's recently diagnosed malignant digestive system GNET. Palliative chemotherapy was administered but the patient died a few days later, 4 months from the initial diagnosis. Awareness of this entity and judicial use of ancillary studies including molecular testing are essential for achieving accurate diagnosis.

Primary Cutaneous Clear Cell Sarcoma, Clinical Outcome With Sentinel Lymph Nodes Status

OBJECTIVES

Primary cutaneous clear cell sarcoma (PCS) is a rare malignancy and difficult to differentiate from melanoma. We investigated factors influencing survival and recurrence.

METHODS

An institutional cancer registry and literature search were used for a retrospective study. Only clear cell sarcoma cases with a primary site of skin and subcutaneous tissue were included. Kaplan-Meier and Cox regression analyses were used to assess survival time and hazard ratios.

RESULTS

Three eligible cases were identified at our institution. In addition, the PubMed and Google Scholar reviews identified 1,878 items, with 23 patients with PCS. The median age was 25 years with 62% female. The tumors ranged in size from 0.4 to 4.5 cm. Cytogenetics showed t(12;22)(q13;q12) in all cases and a unique variant of t(2;22)(q32.3;q12) in one case. Surgery was the most common treatment, followed by chemotherapy/radiation. PCS recurred in 46% of patients with a median relapse-free survival time of 15 months. Only two known PCS-related mortalities were recorded, at 38 and 60 months following initial diagnosis. Smaller tumor size and negative sentinel lymph node biopsy (SLNB) status were significantly associated with a better disease-free survival.

CONCLUSIONS

Tumor size and SLNB status influence PCS survival and recurrence. More research is needed due to the rarity of this disease.

Clear cell sarcoma of soft tissue in pleural cavity: A case report

BACKGROUND

Clear cell sarcoma (CCS) of soft tissue is a rare malignant soft tissue sarcoma usually reported to locate at distal end of extremities and rarely at trunk. Herein, we report a case of CCS in pleural cavity.

CASE SUMMARY

A 31-year-old male was admitted for an uncertain mass in left pleural cavity in routine physical examination without any symptoms. A VATS surgery was performed to remove the tumor. The pathological finding displayed a cystic mass with 6.5 cm at the longest diameter, dark red in section and cysts could be found locally. A strong expression of S-100, HMB45 and Vimentin was detected in immunohistochemical staining, which was inclined to the diagnosis of the CCS of soft tissue. The patient refused chemotherapy, radiotherapy and targeted therapy because of the personal financial situation. Follow-up computed tomography scans were done at the 90^th postoperative day and the 180^th postoperative day, and no obvious sign of recurrence was found till now.

CONCLUSION

CCS of soft tissue also can be found in pleural cavity although in an extremely rare incidence. Radical resection is useful to improve the prognosis.

[Rare childhood kidney tumors]

Pediatric kidney tumors are rare and account for about 6% of all childhood malignancies. By far the most common tumors are nephroblastomas. This review presents rare childhood renal tumors. Mesoblastic nephroma, as tumors of the low risk group, as well as the clear-cell sarcomas of the kidney and malignant rhabdoid tumors, as tumors of the high-risk group, and the so-called anaplastic sarcomas of the kidney will be discussed.Due to the significantly divergent therapy, a correct diagnosis is important. Due to the often overlapping morphology, pathologic diagnosis is often difficult. In addition to the typical morphologic features, the specific immunohistochemical aspects as well as the known molecular changes will be presented.

Prognostic analysis of surgically treated clear cell sarcoma: an analysis of a rare tumor from a single center

BACKGROUND

The objective of this retrospective study was to evaluate the prognostic value of various factors in clear cell sarcoma patients after radical surgery.

METHODS

Forty-two clear cell sarcoma patients from August 2006 to March 2018 were included in the study. Curves of disease-free survival and overall survival were calculated using the Kaplan-Meier method, and univariate and multivariate analyses of various prognostic factors were performed using a Cox proportional hazard regression model. Laboratory test of peripheral blood was recorded before surgery. The optimal cutoff value of systemic inflammatory markers was defined by receiver-operating curve analysis.

RESULTS

The 5-year DFS and 5-year OS rate were 22% and 46%, respectively. The median DFS and OS times were 12 and 41.5 months, respectively. In univariate analysis, there was a significant association between shorter DFS and tumor size larger than 5 cm (p = 0.0043), positive surgical margin (p = 0.0233), and the neutrophil-to-lymphocyte ratio (NLR) higher than 2.73 (p = 0.0009). Furthermore, we observed a significant association between shorter OS and tumor size larger than 5 cm (p = 0.0075), positive surgical margin (p = 0.0101), NLR higher than 2.73 (p = 0.0126), the platelet-to-lymphocyte ratio (PLR) higher than 103.89 (p = 0.0147) and the lymphocyte-to-monocyte ratio (LMR) lower than 4.2 (p = 0.0445). A multivariate analysis demonstrated that the surgical margin (p = 0.013) and NLR (p = 0.001) were significantly associated with DFS. Tumor size (p = 0.010) and NLR (p = 0.013) were independent prognostic factors for OS.

CONCLUSIONS

This study had the second largest sample around the world and preoperative NLR may be a useful prognostic factor in CCS patients after radical surgery.

Mesenchymal Tumors with EWSR1 Gene Rearrangements

Among the various genes that can be rearranged in soft tissue neoplasms associated with nonrandom chromosomal translocations, EWSR1 is the most frequent one to partner with other genes to generate recurrent fusion genes. This leads to a spectrum of clinically and pathologically diverse mesenchymal and nonmesenchymal neoplasms, variably manifesting as small round cell, spindle cell, clear cell or adipocytic tumors, or tumors with distinctive myxoid stroma. This review summarizes the growing list of mesenchymal neoplasms that are associated with EWSR1 gene rearrangements.

Clear cell sarcoma in unusual sites mimicking metastatic melanoma

BACKGROUND

Clear cell sarcoma is an aggressive rare malignant neoplasm with morphologic and immunohistochemical similarities to malignant melanoma. Both disease entities display melanin pigment and melanocytic markers, making differentiation between the two difficult. Although clear cell sarcoma cases in the literature have mainly involved deep soft tissues of the extremities, trunk or limb girdles, we report here two cases of primary clear cell sarcoma in unusual sites and describe their clinicopathologic findings.

CASE SUMMARY

The first case involves a 37-year-old female, who presented with jaw pain and a submandibular mass. The second case involves a 33-year-old male, who presented with back pain and a thoracic spine tumor. Both cases showed tumors with diffuse infiltration of neoplastic cells that were positive for melanocytic markers, and in both cases this finding led to an initial diagnosis of metastatic melanoma. However, further analysis by fluorescence in situ hybridization (commonly known as FISH) showed a rearrangement of the EWS RNA binding protein 1 (EWSR1) gene on chromosome 22q12 in both patients, confirming the diagnosis of clear cell sarcoma.

CONCLUSION

Distinction between clear cell sarcoma and malignant melanoma can be made by FISH, particularly in cases of unusual tumor sites.

[Clear cell sarcoma or gastrointestinal neuroectodermal tumor (GNET) of the tongue? Case report and review of the literature of an extremely rare tumor localization]

Clear cells sarcomas (CCS) are exceptionally rare in the tongue, with, to our knowledge, only three previous reports in anglo-saxon literature. Through our case, we will discuss the differential diagnosis of clear cells tumors of the tongue and bring this tumour closer to the newly described entity of the gastrointestinal tract named "clear cells sarcoma-like gastrointestinal (SCCLGI)", recently renamed "gastrointestinal neuroectodermal tumour (GNET)". SCCLGI/GNET share morphological and molecular characteristics with SCC but had until then been observed only in the digestive tract. Our case could be a lingual localization of a SCCLGI/GNET. SCC and SCCLGI/GNET characteristic molecular profil involves EWSR1-ATF1 [t(12; 22) (q13; q12)] and EWSR1-CREB1 [t(2; 22) (q34; q12)] fusion genes, but it is not specific of these tumours.

Clear cell sarcoma-A review

Clear cell sarcoma (CCS) previously known as malignant melanoma (MM) of the soft tissue, although, similar in morphology to MM, contemporary histopathologic and cytogenetic techniques have made this diagnosis obsolete, as it is now possible to distinguish between CCS and MM. CCS is often diagnosed in young adults with median age of 25 years. Overall mortality is generally poor, and the 5-year survival is between 40 and 60%. Hence, early diagnosis and radical surgery are key in the treatment of this extremely rare malignancy of the soft tissue comprising only about 1% of all sarcomas. This article present an overview of this rare malignancy.

Primary clear cell sarcoma of the tongue and surgical reconstruction: About a rare case report

Clear cell sarcomas (SCC), also called "soft-tissue melanoma", are rare and aggressive tumors that preferentially affect the lower limbs (tendons and fasciae) and which have also been described in head and neck localizations. Their clinical and immunohistochemical mimicry with melanoma makes it difficult to diagnose sarcomas. SCC treatment is mainly focused on large-scale resection surgery with adjuvant radiotherapy because of their low chemo-sensitivity and extreme lymphophilia. In case of head and neck localization, these treatments may lead to function and aesthetic sequelae thus requiring the use of modern techniques of reconstructive surgery. The authors describe the diagnosis, treatment and follow-up of large lingual SCC case using a DIEP free flap reconstruction according to an original technique developed in the department. Given the characteristics of patients with SCC (a high proportion of women between 20 and 40 years old) and its inherent qualities (low morbidity of the donor site, volume delivered and excellent plasticity), the fascio-cutaneous free flap type "DIEP" "taken according to the design of the" Cathedral triptych seems to be a viable choice among the range of reconstruction solutions.

The epidemiology and survivorship of clear cell sarcoma: a National Cancer Database (NCDB) review

PURPOSE

Clear cell sarcoma (CCS) is a rare soft tissue tumor thought to originate from tendons and aponeuroses. This is the largest and most comprehensive study of CCS to the best of our knowledge. In addition, this is the first study to determine the estimated 10-year overall survival, specific treatment modalities including neoadjuvant and adjuvant combinations, and sites of distant metastasis in CCS utilizing a national database.

METHODS

The National Cancer Database (NCDB) was used to study 489 patients diagnosed with CCS from 2004 to 2014. Kaplan-Meier methods were used to estimate 5- and 10-year overall survival, and log-rank tests were used to compare survival amongst stage.

RESULTS

Median age at diagnosis was 39 years. Males and females were equally affected. Race distribution was 78% Caucasian and 15% Black. Most common primary site was lower limb or hip (53%). Percentage of patients with distant organ metastases was 15%, with lung being the most common site (4%). Median overall survival was 57.2 months. Overall estimated 5- and 10-year survival was approximately 50 and 38%, respectively. Approximate 5-year survival for Stages I-IV was 75, 65, 35, and 15%, respectively. Stages at disease presentation were 34% at Stage I, 13% at Stage II, 16% at Stage III, and 38% at Stage IV. Surgery was the most common form of treatment (83%); 34% received radiation and 20% received chemotherapy.

CONCLUSION

The 5-year overall survival for CCS in Stages III and IV was much worse than Stages I and II. Overall estimated 5- and 10-year survival was approximately 50 and 38%, respectively. Men and women were equally affected and had a median age at diagnosis of 39 years. The most common tumor location was lower limb and hip and the most common site of metastases was the lung.

Clear cell sarcoma of the gastrointestinal tract and malignant gastrointestinal neuroectodermal tumour: distinct or related entities? A review

Clear cell sarcoma is an uncommon sarcoma which rarely occurs as a primary tumour in the gastrointestinal tract (CCS-GIT). It shares common molecular genetic abnormalities with the more recently described entity, malignant gastrointestinal neuroectodermal tumour (GNET) but is distinguished by its morphological and immunohistochemical findings. The exact nosological relationship between these tumours continues to be debated. In this review, we present two cases of these rare neoplasms from our files and perform a statistical comparison of all published cases to determine if significant differences exist in their clinicopathological features and biological behaviour. Thirteen cases of CCS-GIT and 58 of GNET were included. CCS-GIT occurred more commonly in males (84.6% vs 46.6%, p = 0.01) and in an older age group (median 57 vs 33 years, p < 0.01). There was no significant difference in their location in the gastrointestinal tract, median tumour size and proportion of cases with an EWSR1-ATF1 vs EWSR1-CREB1 fusion. Median survival for CCS-GIT was 13.5 months and for GNET, 9.5 months (p = 0.78). There was no significant difference in the Kaplan-Meier survival curves for either time to first metastasis (p = 0.88) or overall survival (p = 0.18), including after controlling for tumour size using regression models. Our analysis confirms that aside from morphological variations between these tumours, they also exhibit epidemiological and clinical differences. Despite the prevalent perception that GNET is associated with a more aggressive clinical course, our findings indicate that there is no significant difference in their biological behaviour, although both clearly share a bleak prognosis. Further experience is awaited to determine optimal treatment strategies and whether CCS-GIT and GNET would differ in their response to various therapies.

Clear cell sarcoma arising from paraspinal ligament of thoracic spine: Report of an unusual case

Clear cell sarcoma (CCS) is an unusual but aggressive soft-tissue tumor with an incidence of <1% of all soft-tissue sarcomas. It was previously termed "malignant melanoma of soft parts" due to its resemblance clinically and morphologically. Normally CCS is seen in patients aged 20-40 years. A rare case of CCS of paraspinal ligament in a 5-year-old boy is being reported. Histopathology and immunohistochemistry markers confirmed the diagnosis. The present case is unique since the entity itself is rare and also due to its occurrence in a child.

Renal clear cell sarcoma presenting as a spontaneous renal hematoma: A rare presentation

Clear cell sarcoma of the kidney (CCSK) is an uncommon renal neoplasm of childhood. It represents between 2% and 9% of all pediatric renal tumors, and generally arises before the age of 5 years. It often mimics other pediatric renal tumors. Presently described is the case of a 7-year-old girl who presented with complaints of vomiting and abdominal pain. Abdominal ultrasonography revealed a right renal mass, and the patient developed a renal hematoma a few hours after admission. The patient underwent a nephroureterectomy with a provisional diagnosis of Wilms tumor; however, histopathological examination of a specimen revealed CCSK. CCSK is similar to Wilms tumor in terms of the typical age of appearance and clinical and histopathological features, but the treatment method and prognosis are different. Therefore, the differential diagnosis is very important. This case was presented to draw attention to a rare presentation of clear cell sarcoma. CCSK should be kept in mind in the differential diagnosis of a renal mass.

Clear Cell Sarcoma: A Case Report and Review of Literature

Clear cell sarcoma (CCS), a deep-rooted tumor with a predilection for lower extremities, has a proclivity to involve the tendons and aponeuroses. This sarcoma is seen predominantly around the foot and ankle region. Diagnosis is mainly finalized using histological and immunohistochemical assessment. The main treatment strategy is surgery followed by chemotherapy. An erratic challenge is posed by histological similarity and immunohistochemical overlap to the diagnosis and distinguishing of clear cell sarcoma from primary or metastatic malignant melanoma (MM) which is more common. Here, we described a CCS case located in the left leg of a 37-year-old male patient.

Establishment and proteomic characterization of patient-derived clear cell sarcoma xenografts and cell lines

Clear cell sarcoma (CCS) is an aggressive mesenchymal malignancy characterized by the unique chimeric EWS-ATF1 fusion gene. Patient-derived cancer models are essential tools for the understanding of tumorigenesis and the development of anti-cancer drugs; however, only a limited number of CCS cell lines exist. The objective of this study was to establish patient-derived CCS models. We established patient-derived CCS models from a 43-yr-old female patient. We prepared the patient-derived xenografts (PDXs) from tumor tissues obtained through biopsy or surgery and isolated stable cell lines from PDXs and the original tumor tissue. The presence of gene fusions was examined by RT-PCR, and Sanger sequencing. The established cell lines were characterized by short tandem repeat, viability, colony and spheroid formation, and invasion analyses. Differences in gene enrichment between the primary tumor and cell lines were examined by mass spectrometry and KEGG pathway analysis. The cell lines were maintained for more than 80 passages, and had tumorigenic characteristics such as colony and spheroid formation and invasion. Mass spectrometric proteome analysis demonstrated that the cell lines were enriched for similar but distinct molecular pathways, compared to those in the xenografts and original tumor tissue. Next, tyrosine kinase inhibitors were screened for their suppressive effects on viability. We found that ponatinib, vandetanib, and doxorubicin suppressed the growth of cell lines, and had equivalent IC₅₀ values. Further in-depth investigation and understanding of drug-sensitivity mechanisms will be important for the clinical applications of our cell lines.

Soft Tissue Tumors of Uncertain Histogenesis: A Review for Dermatopathologists

The mesenchymal tumors discussed herein represent a heterogeneous group of neoplasms with distinctive morphologic, immunophenotypic, and molecular genetic features. These uncommon tumors often arise in the dermis and subcutis and can pose a major diagnostic challenge to dermatopathologists because they closely mimic melanoma, carcinoma, fibrous histiocytoma, schwannoma, or granulomatous inflammation. This article reviews the clinical presentation, histopathology, differential diagnosis, and diagnostic pitfalls of epithelioid sarcoma, clear cell sarcoma, perivascular epithelioid cell tumor, ossifying fibromyxoid tumor, pleomorphic hyalinizing angiectatic tumor, and hemosiderotic fibrolipomatous tumor. Associated molecular genetic findings are also briefly reviewed with an emphasis on their diagnostic usefulness.

Trabectedin is a promising antitumor agent potentially inducing melanocytic differentiation for clear cell sarcoma

Clear cell sarcoma is an aggressive soft tissue sarcoma and highly resistant to conventional chemotherapy and radiation therapy. This devastating disease is defined by EWSR1‐ATF1 fusion gene resulting from chromosomal translocation t(12;22)(q13;q12) and characterized by melanocytic differentiation. A marine‐derived antineoplastic agent, trabectedin, inhibits the growth of myxoid liposarcoma and Ewing sarcoma by causing adipogenic differentiation and neural differentiation, respectively. In this study, we examined the antitumor effects and mechanism of action of trabectedin on human clear cell sarcoma cell lines. We showed that trabectedin decreased the cell proliferation of five clear cell sarcoma cell lines in a dose‐dependent manner in vitro and reduced tumor growth of two mouse xenograft models. Flow cytometry and immunoblot analyses in vitro and immunohistochemical analysis in vivo revealed that trabectedin‐induced G2/M cell cycle arrest and apoptosis. Furthermore, trabectedin increased the expression of melanocytic differentiation markers along with downregulation of ERK activity in vitro and the rate of melanin‐positive cells in vivo. These results suggest that trabectedin has potent antitumor activity against clear cell sarcoma cells by inducing cell cycle arrest, apoptosis, and, in part, by promoting melanocytic differentiation through inactivation of ERK signaling. Our present study indicates that trabectedin is a promising differentiation‐inducing agent for clear cell sarcoma.

Complete response of mediastinal clear cell sarcoma to pembrolizumab with radiotherapy

Background

Clear cell sarcoma (CCS) is a rare, aggressive soft tissue sarcoma thought to derive from neural crest and characterized by a 12;22 translocation. The resulting fusion protein directly activates expression of the melanocyte master transcription factor and drives the same down-stream pathways in CCS and melanoma leading to significant clinical parallels between these malignancies. Striking success of immune checkpoint blockade in melanoma has promoted interest in immunotherapy of CCS.

Case presentation

We report the first complete clinical response of a bulky chest wall recurrence of mediastinal CCS in a young woman to anti-PD1 checkpoint blockade with pembrolizumab combined with standard fractionation radiotherapy to enhance regional control and potentially boost the systemic immune response. The treatment was well tolerated with grade 2 skin toxicity within the range expected with radiation alone. Significant reduction in tumor bulk occurred after only 2 radiation fractions and complete response was achieved at 50 Gray.

Conclusion

The complete clinical response observed in our patient suggests synergy between concurrent radiotherapy and PD1 blockade in CCS. This case and the striking parallels between CCS and melanoma indicate the need for prospective trials of immune checkpoint blockade combined with radiotherapy in this rare malignancy.

A case of clear cell sarcoma-A rare malignancy

INTRODUCTION

Clear cell sarcoma (CCS) is a rare tumour of the soft tissue often misdiagnosed, as it shares characteristics with malignant melanoma (MM). Previously, CCS has been characterised, as malignant melanoma of the soft tissue, contemporary immunohistochemical techniques, however, have made this designation obsolete. The true incidence remains unknown, but CCS is believed to represent less than one percent of all sarcomas.

PRESENTATION OF CASE

A 22-year-old patient presented with a mass sized 2.6×2.7×2.7cm of the left gluteal region, pain, and malaise. Initially, the symptoms were interpreted as an infection. Subsequent, pathological diagnosis after surgical removal was tentatively MM albeit definitive pathological diagnosis was CCS.

DISCUSSION

The patient of this case underwent definitive surgical treatment with 2cm margin. In spite of time delay, because of prolonged time for definitive diagnosis, PET-CT and sentinel lymph node biopsy did not show any metastasis. One-year postoperatively, multidisciplinary follow-up is without suspicion of relapse.

CONCLUSION

Accurate and timely diagnosis of CCS are imperative, as initial misdiagnosis, may cause delay and further tumour growth, which is correlated to the prognosis.

Primary mediastinal clear cell sarcoma: a case report and review of the literature

Background

Clear cell sarcoma (CCS) is a rare malignant soft-tissue neoplasm that displays melanocytic markers and exhibits striking histopathological features. The tumour has a predilection for the lower extremities and rarely presents in the mediastinum.

Case presentation

We present a case of primary mediastinal CCS in a 57-year-old man. Computer tomography (CT) revealed a 12 × 12 × 7.5 cm mass in the anterior mediastinum. Microscopically, the tumour mainly consisted of epithelioid cells with oval vesicular nuclei and eosinophilic cytoplasm. Immunohistochemically, the tumour was positive for human melanoma black 45 (HMB-45) and vimentin but negative for S-100 and Melan-A. Fluorescence in situ hybridisation (FISH) showed a translocation involving the EWSR1 gene region.

Conclusion

This report will illustrate that the mediastinum is a potential site for primary CCS and FISH plays an important role in making a conclusive diagnosis.

Biology and treatment of renal tumours in childhood

In Europe, almost 1000 children are diagnosed with a malignant renal tumour each year. The vast majority of cases are nephroblastoma, also known as Wilms' tumour (WT). Most children are treated according to Société Internationale d'Oncologie Pédiatrique Renal Tumour Study Group (SIOP-RTSG) protocols with pre-operative chemotherapy, surgery, and post-operative treatment dependent on stage and histology. Overall survival approaches 90%, but a subgroup of WT, with high-risk histology and/or relapsed disease, still have a much poorer prognosis. Outcome is similarly poor for the rare non-WT, particularly for malignant rhabdoid tumour of the kidney, metastatic clear cell sarcoma of the kidney (CCSK), and metastatic renal cell carcinoma (RCC). Improving outcome and long-term quality of life requires more accurate risk stratification through biological insights. Biomarkers are also needed to signpost potential targeted therapies for high-risk subgroups. Our understanding of Wilms' tumourigenesis is evolving and several signalling pathways, microRNA processing and epigenetics are now known to play pivotal roles. Most rhabdoid tumours display somatic and/or germline mutations in the SMARCB1 gene, whereas CCSK and paediatric RCC reveal a more varied genetic basis, including characteristic translocations. Conducting early-phase trials of targeted therapies is challenging due to the scarcity of patients with refractory or relapsed disease, the rapid progression of relapse and the genetic heterogeneity of the tumours with a low prevalence of individual somatic mutations. A further consideration in improving population survival rates is the geographical variation in outcomes across Europe. This review provides a comprehensive overview of the current biological knowledge of childhood renal tumours alongside the progress achieved through international collaboration. Ongoing collaboration is needed to ensure consistency of outcomes through standardised diagnostics and treatment and incorporation of biomarker research. Together, these objectives constitute the rationale for the forthcoming SIOP-RTSG 'UMBRELLA' study.

Gastrointestinal clear cell sarcoma-like tumour of the ascending colon

INTRODUCTION

A clear cell sarcoma-like gastrointestinal tumour (CCSLGT) is a rare malignant soft tissue sarcoma. In the literature, they are sometimes referred to as malignant gastrointestinal neuroectodermal tumours, clear cell sarcomas or osteoclast rich tumours of the gastrointestinal tract.

CASE HISTORY

We present a case of a CCSLGT arising from the ascending colon of a previously well 22-year-old man presenting with abdominal pain and anaemia. Computed tomography of the abdomen and pelvis showed a 7 cm irregular mass in the right flank that seemed to emerge from the proximal transverse colon. A laparoscopic right hemicolectomy was undertaken to remove the mass. Microscopic pathological examination of the specimen revealed sections of spindle to oval cells with monomorphic nuclei and scant cytoplasm. The cells were arranged in a striking perivascular growth pattern with microcytic breakdown and pseudopapillary formation. Immunohistochemistry analysis showed that the tumour cells removed expressed S100 protein, and were negative for smooth muscle actin, desmin, CD34, CD117, DOG1, HMB-45 and MNF116. Additionally, cytogenetic testing identified EWSR1 gene rearrangement, which was observed by interphase fluorescence in situ hybridisation.

CONCLUSIONS

A complex tumour, a CCSLGT can be thought of in simple terms as a gastrointestinal tract tumour that is S100 protein positive, osteoclast rich, HMB-45 negative and compromises a t(12;22)(q13;q12) gene translocation. These simplified CCSLGT characteristics seem to be described and classified under different aliases in the literature, which makes it difficult to accurately predict the appropriate diagnostic and therapeutic modality required to provide the best clinical care. Given that this case report describes the fourth CCSLGT of primary colonic origins, it may aid future targeted therapies as well as offering epidemiological evidence on prevalence and prognosis.

A giant clear cell sarcoma on right scapular: A case report

Clear-cell sarcoma is a rare and malignant soft tissue tumor most commonly located at the distal end of extremities and rarely at the trunk. Data on the clinical features of the tumor is limited, complicating the analysis of prognosis and establishment of treatment protocols. In our study, we present a case diagnosed with clear-cell sarcoma in his right scapula and treated with tumor resection and chemotherapy, combination of dacarbazine, pharmorubicin and cisplatin. The patient died due to multiple organ failure eight months after operation. Early diagnosis, attentive care, and extended surgical resection combined with adjuvant therapy is of essence in treatment of clear-cell sarcoma.

Oncocytic variant of malignant gastrointestinal neuroectodermal tumor: a potential diagnostic pitfall

Malignant gastrointestinal neuroectodermal tumor (MGNET) is a very rare, aggressive malignant neoplasm that may occur in any location in the gastrointestinal tract. Malignant gastrointestinal neuroectodermal tumors typically consist of sheet-like to pseudopapillary proliferation of primitive-appearing epithelioid cells with a moderate amount of lightly eosinophilic cytoplasm, round nuclei and small nucleoli, often in association with osteoclast-like giant cells. By immunohistochemistry, these tumors show expression of S100 protein and SOX10, in the absence of expression of more specific melanocytic markers (eg, HMB45, Melan A). Genetically, malignant gastrointestinal neuroectodermal tumors are characterized by rearrangements of the EWSR1 or FUS genes with CREB1 or ATF1. We report a case of gastric malignant gastrointestinal neuroectodermal tumor occurring in a 46-year-old woman and showing striking oncocytic cytoplasmic change, a previously undescribed potential diagnostic pitfall. An initial needle biopsy showed large, eosinophilic cells with S100 protein and SOX10 expression and lacking expression of KIT, DOG1, Melan A, keratin, chromogranin, or smooth muscle actin, and was interpreted as representing a granular cell tumor. The subsequent excision specimen showed similar-appearing areas, but also contained small more primitive-appearing areas, lacking oncocytic change and having high nuclear grade and brisk mitotic activity. This resection specimen was initially diagnosed as a malignant granular cell tumor. However subsequent gene expression profiling studies showed an EWSR1-ATF1 fusion, confirmed with fluorescence in situ hybridization for EWSR1, and a final diagnosis of MGNET with oncocytic change was made. This case highlights a previously undescribed pitfall in the diagnosis of MGNET, oncocytic change, and suggests that MGNET should be included in the differential diagnosis for unusual oncocytic neoplasms of the gastrointestinal tract.

Biology and management of clear cell sarcoma: state of the art and future perspectives

INTRODUCTION

Clear cell sarcoma (CCS) is an aggressive tumor, typically developing in tendons or aponeuroses. The outcome of this orphan disease is poor, with 5-year and 10-year survival rates of localized CCS around 60-70% and 40-50%. Once the disease has metastasized, it is usually fatal due to its chemotherapy-resistant nature. Systemic treatment options are poorly standardized and the use of chemotherapy is based on weak scientific evidence.

AREAS COVERED

In this review, we systematically discuss the current scientific evidence for the systemic treatment of CCS, including tyrosine kinase inhibitors, immunotherapy and MET inhibitors. Expert commentary: Recent insights in the biology of CCS have identified new potential therapeutic targets, which should be tested in prospective clinical trials. Whenever possible, patients with metastatic CCS should be included in clinical trials with good biological rationale. Innovative trial methodology and new regulatory mechanisms are required to provide patients with uncommon cancers with active drugs.

Primary pulmonary clear cell sarcoma-the first two reported cases

We report two cases (male patients 50 and 55 years old) of clear cell sarcoma ("melanoma of soft parts") arising in the lung, of which one case showed regional lymph node metastases. Histologically, both tumors displayed varying clear epithelioid and spindle neoplastic cells arranged in storiform and nested growth patterns, separated by thin fibrovascular septa. Immunohistochemical studies demonstrated positive expression of S-100 protein, HMB-45 and Melan-A in one case and S-100 protein only in the other. Fluorescence in situ hybridization showed positive EWSR1 gene rearrangement, and a presence of EWS-ATF1 fusion transcript was confirmed by RT-PCR and sequencing in one case.

Uncommon renal tumors in children: A single center experience

Aims:

Scrutiny over the clinical behaviors, management, and the final outcome of some rare renal neoplasm in order to find out some hidden facts about these tumors which are playing an important role in the disease course and its management.

Materials and Methods:

Retrospective evaluation of uncommon (non-Wilms’) renal neoplasm in the pediatric population in a tertiary care center. Fifteen cases of uncommon renal tumors were treated in our institution over the last 5 years (January 2008 to December 2012). The cases were tabulated in the form of age, sex, mode of presentation, preoperative investigations, intraoperative grading, pathological type, postoperative management and the final outcome. The patients were followed up for 2 years (clinically every 3 months and ultrasonography abdomen in every 6 months for first 2 years) in order to see any evidence of recurrence and complications related to postoperative chemotherapy.

Results:

Out of 15 cases, four cases were clear cell sarcoma (CCS) (26.6%), three cases were rhabdoid tumor (20%), three cases were congenital mesoblastic nephroma (20%), two cases were multilocular cystic nephroma (13.3%), two cases were renal teratoma (13.3%), and one case of teratoid Wilms’ tumor (6.6%). There were two deaths (one CCS and one rhabdoid tumor) due to chemotherapy-related toxicity but no recurrence. Three patients were lost during postoperative follow-up; ten patients are doing well and getting a regular visit in the follow-up clinic.

Conclusion:

The clinical presentations of these uncommon renal tumors are similar to that of Wilms’ tumor. Thus, preoperative diagnosis is difficult even with modern imaging techniques. Some of these tumors (CCS, rhabdoid tumor) are rapidly progressing and have a poor outcome. Hence, early intervention in the form of complete surgical resection of the tumor (whenever possible) and postoperative chemo/radiotherapy are imperative for fruitful outcome.

[Gastro-intestinal neuroectodermal tumor (GNET): A case report of a small intestine tumor with hepatic metastases]

The gastro-intestinal neuroectodermal tumor (GNET) is a rare sarcoma of the digestive tract, which was recently recognised. The knowledge of the morphological, immunohistochemical and molecular diagnostic criteria is necessary to not mistake it for the metastasis of a melanoma or for another sarcoma of the digestive tract as the gastro-intestinal clear cells sarcoma or the malignant peripheral nervous system tumor (MPNST). We report the case of a 41-year-old patient with a GNET of the small intestine with hepatic metastasis. The histological examination showed a diffuse proliferation of epithelioid cells, which only express PS100. The presence EWSR1-ATF1 gene fusions with any melanocytic differentiation leads to the diagnosis of GNET.

Clear cell sarcoma of soft tissue in right parapharyngeal region: report of a rare case

Clear cell sarcoma (CCS), initially named malignant melanoma of soft parts, is a rare malignant neoplasm typically involving deep soft tissue of the extremities, in close proximity to tendons and aponeuroses. Here we describe a case of clear cell sarcoma of the right parapharyngeal region in a young female aged 20 years. MRI detected a mass about 4.4 cm×3.4 cm×3.0 cm, located in the right parapharyngeal area and between the external pterygoid and the medial pterygoid. Microscopically, most of the tumor cells were epithelioid with palely eocinophilic cytoplasm arranged in sheets. Pleophorism of tumor cells were not marked. Immunohistochemical analysis shows that the tumor cells were positive for vimentin, S-100, HMB45 and MelanA, and negative for AE1/AE3, actin-sm, desmin, CD117, TFE-3, and P63. Ki67 index was about 5%.

Potential of boron neutron capture therapy (BNCT) for malignant peripheral nerve sheath tumors (MPNST)

Malignant peripheral nerve sheath tumors (MPNST) are relatively rare neoplasms with poor prognosis. At present there is no effective treatment for MPNST other than surgical resection. Nonetheless, the anti-tumor effect of boron neutron capture therapy (BNCT) was recently demonstrated in two patients with MPNST. Subsequently, tumor-bearing nude mice subcutaneously transplanted with a human MPNST cell line were injected with p-borono-L-phenylalanine (L-BPA) and subjected to BNCT. Pathological studies then revealed that the MPNST cells were selectively destroyed by BNCT.

Bilateral clear cell sarcoma of the kidney

Clear cell sarcoma of the kidney (CCSK) accounts for 2-5% of all pediatric renal malignancies, and is known for its propensity to metastasize to bone and other sites. We are reporting two cases with bilateral CCSK that were diagnosed at our institution. One patient initially presented with bilateral renal masses, as well as pulmonary, hepatic and bone metastasis; while other present only with bilateral masses with no evident distant metastasis. Both patients received aggressive neo-adjuvant chemotherapy to decrease tumor size. One patient completed his designated treatment and initially showed complete remission (CR); eventually suffering from relapse. The other patient's tumor progressed during the course of chemotherapy. Both cases manifested brain dissemination at the time of relapse or progression. This emphasizes the importance of staging stratification in CCSK. This also illustrates CCSK's ability to metastasize to bone and other sites including the brain (a primary relapse site in our cases).