MED15::ATF1-Rearranged Tumor: A Novel Cutaneous Tumor With Melanocytic Differentiation

We recently described novel dermal tumors with melanocytic differentiation and morphologic and biological similarities to cutaneous clear cell sarcoma, including CRTC1::TRIM11 cutaneous tumor, and clear cell tumors with melanocytic differentiation and either ACTIN::MITF or MITF::CREM. Here, we describe a series of 3 patients presenting with tumors reminiscent of CRTC1::TRIM11 cutaneous tumor, found to demonstrate a novel MED15::ATF1 fusion. All 3 patients were children (5-16 years old). Primary excision of case 1 showed a circumscribed wedge-shaped silhouette with peripheral intercalation into collagen fibers and scattered lymphoid aggregates. All 3 tumors abutted the epidermis; one showed a junctional component. Tumors were highly cellular and comprised of monomorphic, oval-to-round epithelioid cells arranged in vague nests and short fascicles in variably fibrotic stroma. Mitotic rate was high (hotspot 6-12/mm2), without atypical mitoses. Necrosis was focally present in case 3. All cases showed strong, diffuse nuclear staining for SOX10 and MITF (2/2) but showed variable expression for S100 protein (1/3) and other melanocytic markers-Melan-A (focal in 2/3), HMB45 (focal in 1/3), and Pan-Melanoma (patchy in 1/1). Whole-exome RNA sequencing demonstrated a MED15::ATF1 fusion without any other notable alterations. Cases 1 and 2 were completely excised without recurrence (12 months). Case 3 developed a grossly apparent regional lymph node spread shortly after primary biopsy. The patient was treated with wide excision, radiation, cervical lymph node dissection (4/46 with >75% lymph node replacement), and neoadjuvant and adjuvant nivolumab (alive without disease at cycle 11). This series is presented to aid in future diagnosis of this novel dermal tumor with melanocytic differentiation and emphasize the potential for aggressive biologic behavior, which should be considered in patient management planning.

Small Intestine Gastrointestinal Clear Cell Sarcoma: A Case Report and Review of the Literature

Gastrointestinal clear cell sarcoma (GICCS)/malignant gastrointestinal neuroectodermal tumor (GNET) is an extremely rare form of cancer with aggressive clinical behavior. It has distinct pathological, immunohistochemical, ultrastructural, and molecular features. Herein, we present the case of a 20-year-old woman with no notable medical history who presented to the outpatient department with complaints of abdominal pain and vomiting. Symptoms had been evolving for 3 months. The physical examination revealed slight abdominal tenderness and melena. Biological investigations revealed iron-deficiency anemia. The upper and lower endoscopies showed no abnormalities. Magnetic resonance enterography revealed small bowel wall thickening of 15 mm × 2 mm. Exploratory laparotomy revealed an ileal mass with mesenteric lymphadenopathy. A wide resection of the mass was then performed. The final pathological report confirmed the diagnosis of small bowel GICCS/GNET. After 11 months of follow-up, the patient presented with mesenteric lymph node metastases.

Compound clear cell sarcoma with EWSR1::CREM fusion

Cutaneous clear cell sarcomas may be confused with melanomas as a result of overlapping histopathology and immunohistochemical staining. We report a case of a 41-year-old woman with a purported history of acral melanoma of the great toe. Twenty-one months after excision of the primary tumor, the patient developed a groin mass, diagnosed as metastatic melanoma on excision. Five months later, a biopsy of a lung mass was reported as metastatic melanoma. The patient was referred to our institution for treatment, which prompted molecular testing on the groin metastasis by targeted next-generation sequencing. Molecular testing results revealed TP53 and TERT promoter mutations and the absence of BRAF, KRAS, and KIT mutations; it also revealed an EWSR1::CREM fusion that was confirmed by Archer FusionPlex. The alleged acral melanoma was re-reviewed, showing an invasive amelanotic spindle cell neoplasm in the dermis with neoplastic nests at the dermal-epidermal junction; the tumor cells expressed markers of melanocytic differentiation but were negative for PRAME and BRAF immunohistochemical staining. Molecular testing of the toe and lung metastasis revealed the same EWSR1::CREM fusion. In light of the molecular findings, the diagnosis was revised to a primary acral compound clear cell sarcoma with EWSR1::CREM fusion.

One step at a time: Melanocytic differentiation in fusion-driven cutaneous neoplasms

As dermatopathologists, we routinely diagnose melanocytic nevi, melanomas, and occasionally melanocytomas in our daily clinical practice. However, it is now clearly established that the presence of melanocytic differentiation in a tumor does not necessarily indicate any of the aforementioned diagnoses. Tumors such as clear cell sarcoma, malignant melanotic nerve sheath tumor, PEComa, melanotic neuroectodermic tumor of infancy, and even certain translocation-associated renal cell carcinomas all share the common characteristic of melanin synthesis. Over the past two decades, with the advent of molecular diagnostics, there has been an explosion of new data and discoveries in this field. Examples such as CRTC1::TRIM11 cutaneous tumors and MITF pathway-activated melanocytic tumors (ACTIN::MITF and MITF::CREM) have been incorporated into the latest edition of the WHO classification of skin tumors (5th ed). In a recent issue, Alexandrescu et al. reported another case of a dermal/subcutaneous melanocytic tumor harboring a MITF::CREM1 translocation. In a separate paper within the current issue, Li et al. present a case of clear cell sarcoma with the rare EWSR1::CREM fusion, which had initially been misdiagnosed as melanoma with regional and distant metastases. We warmly welcome these two very interesting and high-quality articles to our journal, and we eagerly anticipate what the future holds for this fascinating category of tumors.

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.

Navigating through the diagnostic minefield of clear cell sarcoma of soft tissue: Lessons from a challenging case with literature review

Clear cell sarcoma of soft tissue (CCSST) is a rare soft tissue sarcoma occurring in young adults with a predilection for deep soft tissues of the distal extremities. Its overlapping morphology and immunohistochemical profile pose a diagnostic challenge. Herein, we present a rare case of CCSST with a unique immunohistochemical profile arising in an uncommon location. A 36-year-old male presented with a progressively increasing painful swelling in the left supraclavicular region for the last 2 months. Positron emission tomography showed FDG-avid lesions in the left supraclavicular and scapular regions. Fine needle aspiration cytology (FNAC) followed by core needle biopsy was performed. The cytology smears showed predominantly discohesive sheets of polygonal tumor cells with prominent macronucleoli in a vacuolated background. On immunocytochemistry, tumor cells showed positivity for vimentin, HMB45, and S100, confirming the diagnosis of CCSST. Histopathological examination showed sheets of similar tumor cells that were positive for vimentin, HMB45, melan A, CD38, and CD138, representing a potential diagnostic pitfall in the index case. The index report, besides highlighting the characteristic pathologic features of CCSST and its mimics, is unique due to the diffuse positivity of the tumor cells for CD38 and CD138. It is imperative to be aware of this diagnostic pitfall as it may muddle the diagnosis of CCSST.

Unusual Clinical Presentation of Clear Cell Sarcoma in a Young Woman

Clear cell sarcoma (CCS) is a rare but aggressive malignancy that typically occurs in young adults and is characterized by soft tissue tumors of the extremities. CCS can be difficult to distinguish from metastatic melanoma based solely on histology and immunohistochemistry (IHC) because of the significant overlap between them. However, it is imperative to get an accurate clinical diagnosis, as it informs disease staging and treatment options for patient care. Present in approximately 75% of CCS cases, the EWSR1 gene rearrangement detected by fluorescence in situ hybridization (FISH) can help with establishing a diagnosis; the underlying reciprocal translocation has never been reported in cutaneous melanoma. We reviewed a case of a young woman who presented with a confusing picture of widespread lymphadenopathy, cutaneous metastases, and electrolyte derangements and was subsequently diagnosed with metastatic CCS.This case suggests possible value in performing molecular testing when a clinical picture does not correspond with what is expected for melanoma. It also raises the question of whether CCS cases may be underreported. This case highlights an uncommon presentation that may not be recognized as a manifestation of CCS by an oncologist who is not a sarcoma specialist. It is unclear how COVID-19 vaccination contributed to her clinical presentation, and it is also unclear whether an early diagnosis would have changed her clinical outcome.

Clear cell sarcoma of kidney: A mimicker of Wilms' tumor

The differential diagnosis for an abdominal mass in a 2-year-old child is broad and includes lesions of renal, hepatic, gastrointestinal, adrenal, and lymphatic origins. Of these, Wilms' tumor and neuroblastoma are the most common tumors, where Wilms' tumor represents about 92% of renal masses in children. Non-Wilms' renal tumors, rhabdoid tumors, and clear cell sarcoma of the kidney (CCSK) are uncommon. CCSK constitutes approximately 3% of all malignant renal tumors in childhood. In this report, we present a child presenting with a huge renal mass consistent with Wilms' tumor on computed tomography and initial biopsy. However, the final pathologic diagnosis after resection revealed CCSK.

Clear cell sarcoma of soft tissue with plasmacytoid morphology: A rare case report

RATIONALE

Clear cell sarcoma of soft tissue (CCSST) is a rare malignant tumor that occurs in the extremities of young adults. CCSST has been documented to have atypical histopathological features, such as epidermotropism or myxoid differentiation, which may set pitfalls in the differential diagnosis. We report a case of CCSST with plasmacytoid morphology which has never been described.

PATIENT CONCERNS

A 15-year-old male, presented with a 5-cm mass in his left inguinal area.

DIAGNOSIS

Positron emission tomography-computed tomography examination showed nodules in the left groin and the lung, the latter was considered metastasis. A core needle biopsy with the diagnosis of CCSST with plasmacytoid morphology was made according to histology, immunostaining, and molecular analysis.

INTERVENTIONS

The patient received chemotherapy of doxorubicin and ifosfamide.

OUTCOMES

The patient failed to respond to the standard chemotherapy and deceased twelve months after diagnosis.

LESSONS

This special case of CCSST with plasmacytoid features demonstrated a morphological variation never been documented and may easily lead to misdiagnosis. For such cases, molecular analysis is essential to provide solid evidence for accurate diagnosis.

A Case Series of Metastatic Malignant Gastrointestinal Neuroectodermal Tumors and Comprehensive Genomic Profiling Analysis of 20 Cases

Malignant gastrointestinal neuroectodermal tumor (GNET) is an ultra-rare soft tissue sarcoma, therefore often misdiagnosed and has no available standard treatment. Here, we report 3 cases of metastatic GNET with variable clinical courses. Our small case series as well as extensive literature review, further support that GNET is a spectrum of diseases with variable inherent biology and prognosis. Surgical management in the setting of recurrent/metastatic disease may be appropriate for GNET with indolent nature. Response to systemic treatments including chemotherapy and targeted treatments is variable, likely related to heterogenous biology as well. Furthermore, we retrospectively identified 20 additional GNET cases from Foundation Medicine’s genomic database and expanded on their clinicopathological and genomic features. Comprehensive genomic profiling (CGP) with DNA and RNA sequencing of this cohort, in the course of clinical care, demonstrated recurrent EWSR1 chromosomal rearrangements and a sparsity of additional recurrent or driver genomic alterations. All cases had low tumor mutational burden (TMB) and were microsatellite stable.

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.

Primary extragonadal vaginal yolk sac tumour: A case report

INTRODUCTION

Yolk sac tumour (YST) or endodermal sinus tumour is rare and typically seen in gonads.

CASE REPORT

We described a case of extragonadal vaginal YST in a one year and seven months old girl who presented with vaginal discharge and bleeding, and discuss its differential diagnosis and potential pitfalls in immunohistochemistry. She was found to have a suprapubic mass on examination. The serum alpha fetoprotein was 11919.4 ng/mL. Computed tomography of the pelvis revealed a large 6.4 cm heterogenous pelvic mass. Colposcopic examination of the pelvis showed a fungating vaginal mass that was subsequently confirmed as a yolk sac tumour. Immunohistochemically, the malignant cells were positive toward CKAE1/AE3, AFP and glypican-3, as well as CD117.

DISCUSSION

Solid pattern extragonadal vaginal YST may morphologically resemble dysgerminoma that is also CD117 positive, while the glandular pattern YST may have clear cytoplasm and is positive for cytokeratin; hence, may resemble clear cell carcinoma. Being mindful of these potential diagnostic caveats is necessary to prevent misdiagnosis.

A case report of cutaneous melanocytoma with CRTC1-TRIM11 fusion: Is CMCT distinct from clear cell sarcoma of soft tissue?

Pathological diagnosis of dermal melanocytic tumors is often problematic owing to histological resemblance. Recently, cutaneous melanocytoma with CRTC1-TRIM11 (CMCT) was added to this category. However, only six cases have been reported so far. We herein present a case of a 77-year-old Japanese man with CMCT. The patient presented a nodule in the right thigh and underwent surgical resection. Histological examination indicated a well-demarcated 6 × 5 mm-sized tumor nodule in the dermis and subcutis. The tumor was amelanotic, consisting of uniform nests and fascicles of spindled, or epithelioid cells. The melanocytic nature was evident by immunohistochemistry. The CRTC1-TRIM11 fusion was detected by TRIM11 immunostaining, chromogenic in situ hybridization, and RT-PCR/direct sequencing. He has been free from the tumor for 1 year after additional resection. The main differential diagnosis of CMCT includes primary and metastatic dermal malignant melanomas (MM) and dermal/subcutaneous clear cell sarcoma (CCS). Additionally, histological overlap with paraganglioma-like dermal melanocytic tumor was considered. Although some investigators argue that CMCT is a variant of CCS, we think it should be separated from CCS, and subcutaneous/dermal CCS should be confined to tumors with EWSR1-ATF1/ CREB1 fusion. However, longer follow-up and more case studies are needed for revealing the true prognosis of CMCT.

Expression of cyclin D1 in clear cell sarcoma of kidney. Is it useful in differentiating it from its histological mimics?

BACKGROUND

Clear cell sarcoma of the kidney (CCSK) is a rare malignant pediatric renal neoplasm with a heterogeneous histological appearance which often results in misdiagnosis. There are no specific immunohistochemical markers which can help in differentiating CCSK from other pediatric renal neoplasms. Recently Cyclin D1 has been investigated as a possible marker in this regard. In this study, we aim to determine the usefulness of Cyclin D1 in differentiating between CCSK and other pediatric renal neoplasms and to compare our results with those of recently published studies.

METHODS

A total of 48 cases of CCSK, Wilms tumor (WT), renal rhabdoid tumor, mesoblastic nephroma, renal Ewing sarcoma and neuroblastoma were included in the study. All cases were stained with cyclin D1. Extent of Cyclin D1 staining was graded according to percentage of positive tumor cells as diffuse (> 70%), focal (5 to 70%), and negative (< 5%). Intensity of Cyclin D1 staining was graded as strong or 3+, moderate or 2+ and weak or 1 + .

RESULTS

Most or all cases of CCSK, neuroblastoma and renal Ewing sarcoma demonstrated diffuse and strong positivity for Cyclin D1. Most cases of Wilms tumor (epithelial component) also demonstrated diffuse and often strong positivity for Cyclin D1. In most cases of WT, blastemal component was negative.

CONCLUSIONS

Cyclin D1 is a sensitive but not specific immunohistochemical marker for CCSK and many other pediatric renal malignant neoplasms as well as for neuroblastoma. Hence, careful examination of histological features is important in reaching an accurate diagnosis in CCSKs. However, Cyclin D1 is very helpful in distinguishing between blastema-rich WT and CCSK.

Malignant gastrointestinal neuroectodermal tumor (clear cell sarcoma-like tumor of the gastrointestinal tract) of the small intestine in a 12-year-old boy

The aim of this paper is a clinical and anatomopathological demonstration of a malignant lesion, a gastrointestinal neuroectodermal tumor (GNET), as an exceedingly rare cause of ileus in the pediatric population. Specifically, we present the case of a 12-year-old boy who showed dramatic weight loss, hypochromic anemia, fever, dehydration, exaggerated granulation of the terminal ileum, and mechanical ileus due to the obstruction by an intramural tumor of the small intestine. A 50cm-long part of the small intestine with pathological stricture was surgically removed, sampled and routinely fixed and stained with hematoxylin and eosin. The additional immunostains that were preformed were: PAS, S-100, HMB-45, NSE, LCA, CK AE1 / AE3, desmin, SMA, vimentin, CD99, NSE, synaptophysin, WT-1, calretinin, and DOG-1. Moreover, fluorescent in situ hybridization (FISH) with the EWSR1 Break Apart FISH Probe was applied. The neoplasm was composed of nests and alveolar patterns of frankly malignant clear cells with immunoreactivity to S-100, vimentin, and CD 99. The FISH technique detected chromosomal breaking at 22q12. The tumor metastasized to both the mesenteric lymph nodes and a number of hepatic segments. With several chemotherapy protocols, repeat laparotomies, and liver thermal ablations, the patient had a 1.5-year-long survival from the moment of diagnosis. The diagnosis of this malignancy requires both histopathological evaluation and molecular analysis, and the follow-up is based on careful clinical imaging of the neoplastic spread in order to apply proper surgical and oncological treatments. In conclusion, the clinical course of GNET was highly aggressive.

Clear-cell sarcoma of tendons and aponeuroses in the right genitofemoral line - a case report

INTRODUCTION

Our case report presents a rare occurrence of clear cell sarcoma in the genitofemoral line region that has not been described to date.

CASE REPORT

A 57-year-old male patient with clear-cell sarcoma of tendons and aponeuroses is presented. The patient underwent a radical operation and adjuvant radiotherapy.

CONCLUSION

The patient is still alive, in a good health condition, without local recurrence or generalised disease. Key words: clear-cell sarcoma of tendons and aponeuroses - genitofemoral line.

Diagnosis, Classification, and Management of Soft Tissue Sarcomas

BACKGROUND

Soft tissue sarcomas are challenging to oncologists due to their unique character, the infrequency of their occurrence, and the difficulties in predicting outcomes. Advances in imaging, as well as improvements in surgical techniques and adjunctive treatment methods, have improved care for patients with these unusual disorders.

METHODS

The various types of soft tissue tumors are defined, and the statistics for the Orthopaedic Oncology Group in relation to them are reviewed and compared with literature references.

RESULTS

The overall survival rate for 1,220 tumors treated at our institute from June 1972 to June of 2001 was 72%, with a wide range. Patients with leiomyosarcomas, clear cell sarcomas, and malignant fibrous histiocytomas had a poorer survival rate, while those with fibrosarcomas, liposarcomas, and neurofibrosarcomas fared better. Outcome was affected by patient age, tumor anatomic site, tumor stage, and a history of recurrence.

CONCLUSIONS

Competent imaging, predictive immunological and genetic studies, improved surgery, and newer methods of adjunctive and neoadjunctive treatment should result in improvements in outcomes for patients with these tumors.

Multiple clear-cell sarcomas of small intestine with parotid gland metastasis: A case report

Clear-cell sarcoma is a rare, malignant soft tissue tumor that displays melanocytic differentiation with a distinct molecular profile. It is rarely localized in the gastrointestinal tract. Herein we reported a case of multiple synchronous clear-cell sarcomas of the gastrointestinal tract with parotid gland metastasis. A 51-year-old male patient presented with a growing painless mass under the right ear. A preoperative positron emission tomography/computed tomography showed multiple intestinal masses and a mass in the right parotid with increased glucose uptake, and he underwent operative treatment with resection of three tumors in the jejunum and ileum and then received a right parotidectomy. Postoperative pathological examination showed that cells in the intestinal tumor were consistent with clear-cell sarcoma of the gastrointestinal tract, and the malignant cells in the parotid gland were similar to the intestinal tumor. Immunohistochemical studies revealed positive expression of HMB-45, Melan-A, and S-100. EWSR1 gene fusion transcripts were undetectable by fluorescence in situ hybridization.

Clear cell sarcoma of vulva. A case report

We report the case of a 67-year-old female with clear cell sarcoma (CCS) of the vulva. Grossly, the tumor was a partly exophytical vulvar mass, measuring 20 x 15 cm. At the time of presentation, the patient showed metastases to the lung, inguinal and pelvic lymph nodes. Histologically, the tumor consisted of oval or spindle cells with only mild nuclear pleomorphism and rare mitoses (up to 2/10 HPF). The cytoplasm was pale eosinophilic or clear. The tumor cells were arranged in confluent sheets. There were large areas of necrosis and surface ulceration. Immunohistochemically, the tumor cells showed expression of S-100 protein and focal melan A and HMB45 expression. Fluorescent in situ hybridization analysis revealed rearrangement of the EWSR1 gene. To the best of our knowledge, this is the first report of CCS arising in the vulva.

[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.

Non-mesenchymal Mimics of Sarcoma

A variety of different non-mesenchymal neoplasms may mimic sarcoma, in particular sarcomatoid carcinoma and melanoma, but also mesothelioma and rarely some lymphomas. This article reviews the key clinical and histologic features of such neoplasms in different settings, along with the use of ancillary studies to help identify the tumor types most frequently misdiagnosed as sarcoma.

DNA methylation profile distinguishes clear cell sarcoma of the kidney from other pediatric renal tumors

A number of specific, distinct neoplastic entities occur in the pediatric kidney, including Wilms' tumor, clear cell sarcoma of the kidney (CCSK), congenital mesoblastic nephroma (CMN), rhabdoid tumor of the kidney (RTK), and the Ewing's sarcoma family of tumors (ESFT). By employing DNA methylation profiling using Illumina Infinium HumanMethylation27, we analyzed the epigenetic characteristics of the sarcomas including CCSK, RTK, and ESFT in comparison with those of the non-neoplastic kidney (NK), and these tumors exhibited distinct DNA methylation profiles in a tumor-type-specific manner. CCSK is the most frequently hypermethylated, but least frequently hypomethylated, at CpG sites among these sarcomas, and exhibited 490 hypermethylated and 46 hypomethylated CpG sites in compared with NK. We further validated the results by MassARRAY, and revealed that a combination of four genes was sufficient for the DNA methylation profile-based differentiation of these tumors by clustering analysis. Furthermore, THBS1 CpG sites were found to be specifically hypermethylated in CCSK and, thus, the DNA methylation status of these THBS1 sites alone was sufficient for the distinction of CCSK from other pediatric renal tumors, including Wilms' tumor and CMN. Moreover, combined bisulfite restriction analysis could be applied for the detection of hypermethylation of a THBS1 CpG site. Besides the biological significance in the pathogenesis, the DNA methylation profile should be useful for the differential diagnosis of pediatric renal tumors.

Primary sarcoma of the anterior cruciate ligament - a case report

Clear cell sarcoma of tendons and aponeuroses (CCSTA) is a rare, aggressive soft tissue malignancy, which is found in intimate association with tendon, aponeurosis or fascia. It has not previously been reported in association with intraarticular ligaments. We report the first case of an intraarticular CCSTA, in this case of the anterior cruciate ligament and describe the diagnostic and treatment challenges of intraarticular tumours of the knee.

A case of clear cell sarcoma of the kidney

Clear cell renal sarcoma is a rare tumor and comprises 4% of primary pediatric malignant renal tumors. It is known as an aggressive tumor with poor prognosis. Clinically and radiographically, it resembles Wilms tumor. We present a case of a child with an abdominal mass that was diagnosed as clear cell sarcoma of her right kidney.

[Clear-cell sarcoma of the kidney: about a paediatric case]

Clear-cell sarcoma of the kidney (CCSK) is a rare malignant tumor of childhood, known for its aggressiveness, its tendency to recurrence and to metastasis to bone. We report an observation of a child of 48 months carrying a large abdominal mass. The diagnosis of the SCCR was made on biopsy, since imaging remained uncertain as to the renal origin of the mass. Indeed, our observation underlines the difficulty of its diagnosis. Excepting the morphological aspect, there is no criterion for its recognition. Its prognosis has been improved by the new treatments.

[Diagnostic image (350). A woman with a swollen knee. Clear cell sarcoma]

A 31-year-old woman presented with a slowly growing mass anterior from the right patella, due to a clear cell sarcoma.

Clear cell sarcoma of the ileum: report of a case and review of literature

Clear cell sarcoma (CCS) is a high grade soft tissue sarcoma with a distinct molecular profile and with morphological features resembling those of melanoma. CCS has been rarely described in other locations other than the soft tissues, including the gastrointestinal tract. In this study, we report a case of CCS arising in the ileum of a 31-year-old woman. Histologically, the tumor involved the entire thickness of the intestinal wall. Tumor cells were polygonal or fusiform, with clear or eosinophilic cytoplasm, arranged in a uniform nested to fascicular growth pattern. Immunohistochemical studies revealed strong positivity for vimentin and S-100 protein. HMB-45, Melan-A, tyrosinase, cytokeratins, EMA, smooth muscle actin, CD34, CD31, CD117, CD99, synaptophysin, chromogranin A, CD56, and NSE were negative. Fluorescence in situ hybridization analysis demonstrated the presence of a t(12;22)(q13;q12) translocation, the diagnostic hallmark of CCS of soft parts. The present case, together with a detailed review of the literature on this topic, demonstrates that the gastrointestinal tract is a possible site of CCS of soft tissues and that making a reliable diagnosis of this tumor requires cytogenetic or molecular diagnostic investigations.

Clear cell sarcoma of the kidney--a study of seven cases over a period of three years

Clear cell sarcoma of the kidney (CCSK) can display diverse morphological patterns and mimic various other pediatric renal tumors. An accurate diagnosis of this tumour is important considering the therapeutic and prognostic implications.

AIM

The present study was undertaken to describe the various histological patterns of CCSK. The histology of 7 cases and the available case files of CCSK accrued over a period of3 years were reviewed. Immunohistochemical (IHC) stains were performed in 3 cases. The histological patterns observed in this study were classical (observed in 4 cases), epithelioid trabecular, myxoid, palisading and hyaline sclerosis types. IHC revealed reactivity to vimentin and non-reactivity to cytokeratin, desmin, smooth muscle actin, neuron specific enolase (NSE) and S-100 protein. Since CCSK is essentially a histological diagnosis, the importance of an accurate diagnosis of CCSK by a pathologist cannot be overemphasized. This study describes the various histological patterns that can be observed in CCSK.

Bone metastases of clear cell sarcoma of the kidney diagnosed by fine needle aspiration cytology. A case report

BACKGROUND

Clear cell sarcoma of the kidney (CCSK) was first recognized from its predilection to metastasize to bone. While there are many case reports in documenting the diagnosis of CCSK by fine needle aspiration cytology (FNAC), this is the first case in which FNAC was instrumental in diagnosing the condition from a metastatic site.

CASE

A 2-year-old presented with multiple bone lesions. Fine needle aspirates from these lesions showed a polygonal cell population with eccentrically diagnose both pri placed, lobulated nuclei. The diagnosis of metastatic clear cell sarcoma offered on FNAC prompted a search for the primary renal lesion.

CONCLUSION

FNAC is a rapid, cost-effective technique and must be used to type pediatric tumors so that an appropriate chemotherapeutic regimen can be commenced promptly.

Clear Cell Sarcoma of Tendons and Aponeuroses: A Review

Clear cell sarcoma of tendons and aponeuroses, also referred to as malignant melanoma of soft parts, is a rare malignancy derived from neural crest cells. It usually presents in the distal lower extremities of young adults, frequently attached to tendons or aponeuroses. It behaves like a high-grade soft tissue sarcoma and is associated with poor overall survival. Magnetic resonance imaging studies of the lesion reveal T1 hypointensity, T2 hyperintensity, and gadolinium uptake. Grossly, the tumor is usually circumscribed with a histologic pattern of uniform polygonal to fusiform cells with clear to pale eosinophilic cytoplasm divided into variably sized clusters by fibrous septa. Immunohistochemical studies in most cases show that the neoplastic cells are positive with HMB-45 and react with antibody against S100 protein. Most cases show a reciprocal cytogenetic translocation t(12;22)(q13;q12) that creates a unique chimeric fusion EWSR1/ATF1 gene transcript. Metastasis occurs mainly to regional lymph nodes and lungs. Poor prognostic indicators include a tumor size equal to or more than 5 cm, presence of metastasis, and necrosis. The mainstay of treatment is wide excision of the tumor. The use of sentinel lymph node biopsy may become an important procedure in detecting occult regional metastasis and guiding the extent of surgery. The beneficial effects of adjuvant chemotherapy and radiotherapy have not been fully evaluated. This article provides a short overview of the current knowledge of clear cell sarcoma of tendons and aponeuroses.

Is clear cell sarcoma a malignant form of psammomatous melanotic schwannoma?

✓The authors present a case of clear cell sarcoma (CCS) in which the tumor originated in the S-1 nerve root and had been previously diagnosed as psammomatous melanotic schwannoma (PMS). This is the third case of a spinal nerve root origin for CCS reported in the English-language literature. The similar histogenesis of CCS and malignant melanoma supports the hypothesis that biological agents or immunotherapy are potentially important areas of investigation.

The patient underwent S1–3 laminectomy and gross-total resection of the mass lesion. The border of the resection was extended 1 cm distal to the tumor margin. The postoperative period was uneventful. The new histopathological diagnosis was CCS (malignant melanoma of soft tissue). Despite total resection, the patient returned with disseminated disease at the 18-month follow-up visit. His follow-up magnetic resonance image of the lumbar spine revealed sacral L5–S3 involvement of the vertebral bodies along with disseminated cauda equina seeding.

A CCS originating from peripheral nerves is quite rare. The histopathological and immunohistochemical appearance of CCSs resembles those of PMSs. Surgery should be the first choice of treatment.

[Clear cell sarcoma of the chest wall; report of a case]

Clear cell sarcoma is a rare malignant soft tissue neoplasm that usually arises adjacent to tendons or aponeuroses. The principal sites of this neoplasm are the extremities, but tumors do occur in the trunk on rare occasions. A case had a checkup for chest bachache with a 21-year-old woman, and it was diagnosed as the right chest wall tumor. We performed the en bloc resection of parts of the 7th and 8th ribs. Composix mesh was fixed to cover a deficit in the chest wall. The pathological diagnosis was clear cell sarcoma of the chest wall. The postoperative course was uneventful. She has shown no symptoms or signs of recurrence during 14 months of follow-up.

Clear cell sarcoma of the small bowel: a potential pitfall. Case report

Clear cell sarcoma (soft-part melanoma) is a very rare entity with a distinctive histopathologic and molecular profile. Herein, we present the sixth reported case of a primary gastrointestinal clear cell sarcoma discovered in a 21-year-old woman. The patient underwent numerous tests prior to the diagnosis of her small bowel pathology, including the use of capsule endoscopy, which allowed for visualization and final localization of the tumour. Additionally, we discuss this rare type of sarcoma that affects young adults and has a poor prognosis characterized by the balanced chromosomal translocation t(12;22)(q13;q12) with special emphasis on the necessity for pathologists to be able to distinguish it from melanoma -- potentially a major pitfall in diagnosis.

Sarcome à cellules claires du rein chez l’adulte : à propos d’un cas

Clear cell sarcoma of the kidney rarely affects adults. It has an aggressive evolution, with a high rate of recurrence and mortality. We report the case of a 58 year old man with clear cell sarcoma of the kidney and discuss the benefit and value of medical imaging for management.

[Clear cell chondrosarcoma of the larynx. A rare tumor in an uncommon location]

Clear cell chondrosarcoma is a rare bone tumor of low malignancy. It constitutes only 2% of all chondrosarcomas and shows a particular predilection for the epiphyses of long bones. So far, there have only been three cases of clear cell chondrosarcoma of the larynx published in the literature. We report the case of a 46 year old man who suffered from slowly worsening dyspnoea. Diagnostic evaluation revealed a directly subglottic stenosis of the larynx, narrowing the lumen to 1/3. When we tried to resect the stenosis via splitting the ring cartilage from outside, tumorous infiltration of the whole ring cartilage was found. Extended biopsies were taken and histology revealed a clear cell chondrosarcoma. The therapy of choice for this tumor is wide surgical resection. Additional radio- and/or chemotherapy are not recommended. Therefore, the patient underwent laryngectomy. Histologically, the clear cell chondrosarcoma can be easily confused with the highly malignant osteosarcoma or the conventional chondrosarcoma, both requiring more aggressive treatment. Thus, clear cell chondrosarcoma should be kept in mind and, when necessary, a reference histology by a bone tumor register should be requested.

Association of the t(12;22)(q13;q12) EWS/ATF1 rearrangement with polyphenotypic round cell sarcoma of bone: a case report

The t(12;22)(q13;q12) chromosomal rearrangement results in an EWS/ATF1 fusion transcript and is associated with clear cell sarcoma (CCS). CCS is an uncommon tumor arising in tendons and aponeuroses of the extremities and shows evidence of melanocytic differentiation at the light microscopic, immunohistochemical, and/or ultrastructural level. Only 5 cases have been reported to arise in bone, none of which had molecular confirmation of the diagnosis. The current report describes a 7-year-old girl with a primary round cell sarcoma of the left humerus showing polyphenotypic differentiation on immunohistochemical analysis. Antibodies directed at melanocytic antigens were negative, and there was no evidence of melanocytic differentiation by light microscopy or ultrastructural analysis. Cytogenetic analysis revealed rearrangement of the EWS locus within 22q12. RT-PCR and sequence analysis revealed the presence of a fusion transcript bringing together exon 7 of EWS with exon 5 of ATF1, consistent with a type 2 transcript reported in association with CCS. However, given the lack of morphologic features usually present in CCS, a diagnosis of polyphenotypic round cell sarcoma was made. This tumor thus expands the spectrum of neoplasms associated with the t(12;22)(q13;q12) rearrangement.

Clear cell myomelanocytic tumor (PEComa) of the duodenum in a child with a history of neuroblastoma

We report herein a case of digestive clear cell myomelanocytic tumor (PEComa) that is unique in its location and presentation. The lesion, located in the duodenal wall, was diagnosed in a child with a history of cervical neuroblastoma that was in remission after surgical resection and chemotherapy. The diagnosis was obtained by examination of a biopsy specimen taken during laparoscopy. The decision was made to perform surgical resection. Examination of the surgical specimen confirmed the diagnosis of PEComa. No metastasis was found. After 2 years of follow-up, the patient is alive, without evidence of metastasis or recurrence. This case highlights the distinctive characteristics of the cells in PEComa, recognizable even on limited biopsy material. It also suggests a possible association between PEComa and neuroblastoma, 2 unusual tumors that belong to the spectrum of lesions known to occur in patients with tuberous sclerosis and that may share a possible common pathogenetic mechanism.

Clear cell sarcoma-like tumor with osteoclast-like giant cells in the small bowel: further evidence for a new tumor entity

Most mesenchymal neoplasms of the gastrointestinal tract belong to the category of gastrointestinal stromal tumors (GISTs) and are characterized by the immunohistochemical expression of KIT receptor. In cases without detectable KIT receptor expression several differential diagnoses have to be taken into consideration. Here, we report a case of a 41-year-old man with a tumor of the small bowel composed of large epithelioid tumor cells arranged in solid and alveolar sheets including scattered osteoclast-like multinucleated giant cells. Immunohistochemically, the tumor cells expressed strongly S-100 protein, vimentin, and to a lesser extent, bcl-2. HMB-45, melan-A, KIT receptor, desmin, smooth-muscle actin, and CD-34 were not detectable. Ki-67 index was 20%. The diagnosis was established by 2 different FISH strategies demostrating the presence of a t(12;22)(q13;q12) translocation, the diagnostic hallmark of clear cell sarcoma of soft parts. Our results provide further evidence for the existence of a new tumor entity designated gastrointestinal clear cell sarcoma with osteoclast-like giant cells. The diagnosis of this entity should be considered in the presence of S-100-positive tumors of the gastrointestinal tract containing multinucleated giant cells and can be established by FISH analysis.

Diagnosis of clear cell sarcoma by real-time reverse transcriptase-polymerase chain reaction analysis of paraffin embedded tissues

BACKGROUND

Clear cell sarcoma (CCS) is a rare tumor with a very poor prognosis that occurs predominantly in the distal extremities of young adults. Most patients bear the t(12;22) reciprocal translocation, which involves the EWS and ATF1 genes. The diagnosis of CCS usually is easy but may be challenging in unusual sites, and the detection of EWS-ATF1 fusion transcripts is helpful to rule out a metastatic melanoma.

METHODS

Forty-four patients with CCS and 14 conventional melanomas were examined for the presence of EWS-ATF1 transcripts by using real-time polymerase chain reaction (PCR) analysis on paraffin embedded tissues, including frozen samples for 9 CCS samples and 9 melanoma samples. Prior to molecular analysis, the diagnosis of CCS was considered certain in 35 patients and as probable in 9 patients on the basis of location, histologic features, and immunohistochemical profile. Treatment modalities and follow-up were available for 41 patients with CCS.

RESULTS

EWS-ATF1 fusion transcripts were detected in 38 paraffin embedded CCS tissues (86% of all samples; 93% of interpretable samples), 3 samples (7%) were negative, and 3 samples (7%) were considered uninterpretable. Fusion transcripts were detected in 7 of 9 samples for which the diagnosis of CCS was considered probable. EWS-ATF1 transcripts were not detected in the 14 samples of melanoma. Results from frozen tissues were concordant with those from all corresponding paraffin embedded samples. Twenty-eight of 41 patients (68%) experienced lymph node and/or distant metastasis, and the 5 year-survival rate was 44%. Mitotic index and histologic grade were predictive of survival and distant metastasis.

CONCLUSIONS

The results of this study showed that the molecular detection of EWS-ATF1 fusion transcript by real-time PCR on paraffin embedded tissues is a sensitive and specific method for the diagnosis of CCS. It is an efficient tool for the diagnosis of unusual tumors, especially with regard to its distinction from melanoma. The current results also confirmed the poor prognosis for patients with this tumor type. Mitotic index and grade were predictive factors for survival and distant metastasis.