This editorial comments on the study by Liu et al investigating pancreatic metastasis of clear cell sarcoma (CCS) published in the World Journal of Clinical Cases. CCS is a rare and aggressive melanocytic tumor, that typically arises from tendons and aponeuroses of the limbs, and metastasizes to the lungs, bones, and brain. However, pancreatic metastasis has rarely been reported, presenting unique diagnostic and therapeutic challenges. Elucidating the clinical characteristics, imaging features, prognostic factors, and treatment outcomes of patients with pancreatic CCS metastasis is crucial. Surgery remains an effective management strategy for CCS. However, the high recurrence rate and low effectiveness of traditional adjuvant treatments necessitate a shift towards more personalized and targeted treatment plans. Research is needed to investigate and validate novel therapeutic approaches specifically tailored to the distinct genetic and molecular characteristics of rare malignancies like CCS. Additionally, the development of late metastases after a long disease-free interval is common in CCS patients. Therefore, routine postoperative surveillance for metastasis using computed tomography, magnetic resonance imaging, bone scans, and positron emission tomography scans is crucial. Moving forward, enhanced collaboration, investigation, and creative thinking among scientists, medical professionals, and legislators are essential to gain a deeper understanding of these rare presentations.

Clear cell sarcoma (CCS) is a type of malignant tumor that can arise from tendons and aponeuroses. This malignant proliferation of cells with melanocytic lineage normally occurs in young patients, and it is normally identified in extremities. However, different sites including gastrointestinal organs are also described. Due difficulties in the molecular and histopathology evaluation, the diagnosis is often confused with malignant melanoma. Most cases are treated with surgical resection, but overall, the prognosis is poor. In this editorial, we will discuss a very interesting case of CCS identified in the pancreas. We will discuss the literature and controversies in the management of this type of cancer. Furthermore, we will address molecular strategies to be incorporated in those cases to better understand the primary location of the tumor. Finally, future perspectives of the field and new strategies of treatment will be described.

Histiocytic neoplasms (HNs) in adults have been reported to be associated with a high prevalence of coexisting haematological and solid malignancies. While a proportion of coexisting HNs and haematological malignancies share identical genetic alterations, the genetic association between HNs and solid malignancies has scarcely been reported. We report a case of Rosai-Dorfman disease (RDD) complicated by coexisting clear cell sarcoma (CCS). RDD is a rare HN. CCS is an ultrarare soft tissue sarcoma with a poor prognosis. Mutation analysis with whole-exome sequencing revealed six shared somatic alterations including NRAS p.G12S and TP53 c.559+1G>A in both the RDD and CCS tissue. This is the first evidence of a clonal relationship between RDD and solid malignancies using mutational analysis. We hypothesise that neural crest cells, which originate in CCS, are likely the common cells of origin for RDD and CCS. This case helps to unravel the underlying clinicopathological mechanisms of increased association of solid malignancies in HNs. © 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

BACKGROUND: Clear cell sarcoma is rare, so no reports have previously characterized its national profiles. We examined the nationwide epidemiology and clinical outcomes of patients with clear cell sarcoma based on the National Cancer Registry in Japan.
METHODS: Overall, 23 522 patients with soft tissue sarcoma-entered in the National Cancer Registry in 2016-2019 using the International Classification of Diseases for Oncology, Third Edition cancer topography and morphology codes-were enrolled in either the clear cell or the non-clear cell sarcoma group. Data extracted included: demographics (sex and age), tumor details (reason for diagnosis, tumor location, histology and stage), hospital volume and facility type, treatment and prognosis for each patient.
RESULTS: Of 23 522 soft tissue sarcoma patients, 122 were enrolled in the clear cell sarcoma group and 23 400 in the non-clear cell sarcoma group. The incidence of clear cell sarcoma was 0.52% of all soft tissue sarcoma, with an age-adjusted incidence of 0.024/100 000/year. The age at diagnosis was significantly younger, and more tumors were at the localized stage in the clear cell than the non-clear cell sarcoma group. In addition, the overall survival in the clear cell group was worse than in the non-clear cell group (P < 0.001). Of 122 patients with clear cell sarcoma, the localized stage, surgical treatment and treatment without chemotherapy were associated with better overall survival in the univariate analyses.
CONCLUSIONS: The present study is the first to have clarified the epidemiology, clinical features, treatment, prognosis and significant factors affecting the prognosis of patients with clear cell sarcoma in Japan.

BACKGROUND: Clear cell sarcoma (CCS) and alveolar soft part sarcoma (ASPS) are rare, and standard systemic therapy is not established except for sunitinib in ASPS. It is known that CCS and ASPS have a common biological feature of melanoma and Xp11.2/TFE3 translocation renal cell carcinoma, and immune-checkpoint inhibitors (ICIs) are effective in these tumors. The authors conducted a phase 2 trial to evaluate the efficacy and safety of nivolumab for CCS and ASPS.
METHODS: The number of patients expected to be enrolled was 15-25 and was determined based on the Bayesian design. The primary end point was the confirmed objective response rate (ORR) according to the central review and the secondary end points included ORR, progression-free survival (PFS), overall survival (OS), and safety.
RESULTS: A total of 26 patients (CCS, 12; ASPS, 14) were enrolled. Efficacy and safety were analyzed on 25 and 26 patients, respectively. The minimum number of responses required for a positive conclusion regarding the efficacy was four. However, only one patient (4.0%) with ASPS had a partial response. Complete response, stable disease, progression disease, and not evaluable were 0%, 60%, 32%, and 4.0%, respectively. Adverse events of grade 3 or 4 occurred in 57.7% (15 of 26). The median PFS was 4.9 months (95% confidence interval [CI], 3.7-8.6 months) and the median OS was 15.8 months (95% CI, 8.2-not reached).
CONCLUSIONS: The primary end point of the ORR was not met for CCS and ASPS on the central review. Further studies are needed to evaluate ICIs in patients with ASPS.

暂无摘要。

Primary or secondary clear cell sarcoma of the pancreas is an exceedingly rare and aggressive disease. In addition to pathology, molecular analysis is pivotal in differential diagnosis, especially with malignant melanoma. A key aspect in identifying clear cell sarcoma is specific genetic alterations, notably the translocation of t(12;22) (q13;q13), a diagnostic hallmark of this sarcoma subtype, which is absent in malignant melanoma. Treatment of primary clear cell sarcoma of the pancreas is the same as that for adenocarcinoma.

Background: Clear cell sarcoma (CCS) is an extremely rare form of sarcoma representing less than 1% of all soft-tissue sarcomas. It has morphological, structural, and immunohistochemical similarities to malignant melanoma, affecting young adults and equally affecting both sexes, and is usually located in the tendinous sheaths and aponeuroses of the limbs. Gastrointestinal localization is exceptional, with less than 100 cases reported thus far. The gene fusion of activating transcription factor 1 (ATF1) and the Ewing sarcoma breakpoint region 1 (EWSR1) are pathognomonic for clear cell sarcoma, representing the key to the diagnosis. CCS is an extremely aggressive tumor, with >30% having distant or lymphatic metastasis at the time of diagnostic, and it has a high recurrence rate of over 80% in the first year after diagnosis and a high tendency for metastatic dissemination. Given the rarity of this tumor, there is no standardized treatment. Early diagnosis and radical surgery are essential in the treatment of CCS both for the primary tumor and for recurrence or metastasis. Chemo-radiotherapy has very little effect and is rarely indicated, and the role of targeted therapies is still under investigation. Case presentation: We present an extremely rare case of intestinal CSS in a 44-year-old Caucasian female. The patient, asymptomatic, first presented for a routine checkup and was diagnosed with mild iron-deficiency anemia. Given her family history of multiple digestive cancers, additional investigations were requested (gastroscopy, colonoscopy, tumoral markers and imaging) and the results were all within normal limits. In the subsequent period, the patient experienced mild diffuse recurrent abdominal pain, which occurred every 2-3 months. Two years later, the patient presented with symptoms of intestinal obstruction and underwent an emergency laparotomy followed by segmental enterectomy and regional lymphadenectomy for stenotic tumor of the jejunum. Histology, immunohistochemistry, and genetic testing established the diagnosis of CCS. No adjuvant therapy was indicated. Initially, no signs of recurrence or metastasis were detected, but after 30 and 46 months, respectively, from the primary treatment, the patient developed liver metastasis and pericolic peritoneal implants treated by atypical hepatic resections and right hemicolectomy. The patient remains under observation.

This article presents a comprehensive case report on an uncommon instance of metastatic clear cell sarcoma (CCS) originating from the pancreas. The high mortality rate of pancreatic carcinoma underscores the importance of precise diagnosis and early detection. The authors report a novel case of CCS with pancreatic metastasis, detailing successful surgical intervention through distal pancreatectomy and splenectomy, resulting in favourable outcomes. This study highlights the standard role of surgery in treating advanced CCS and emphasizes preoperative imaging and thorough patient history assessment. This article also underscores the necessity for long-term surveillance due to the potential for recurrence or metastasis. Despite the favourable recovery postsurgery, the absence of subsequent follow-up evaluation prompts consideration of the need for extended monitoring. This article raises questions about the nature of the pancreatic lesion and suggests the possibility of a primary lesion. Further evidence is crucial to establish the correlation between the features related to the development of the patient\'s primary and metastatic tumours. In conclusion, this study offers valuable insights into metastatic CCS of the pancreas, highlighting the importance of regular postoperative follow-up for improved outcomes through early detection and intervention.

In this editorial based on a case report, we delve into a seldom-seen occurrence of clear cell sarcoma featuring pancreatic metastasis in a 47-year-old male patient. Recognized for its typical tendency to metastasize to the lungs, bones, and brain, clear cell sarcoma rarely extends its reach to the pancreas. Despite the initial absence of discernible abnormalities during the patient\'s physical examination, the manifestation of abdominal pain prompted further investigation. Subsequent abdominal computed tomography brought to light the presence of a pancreatic tumor, culminating in the definitive diagnosis of clear cell sarcoma with pancreatic metastasis. The successful management of this atypical presentation involved a series of surgical interventions, including distal pancreatectomy and splenectomy. This report not only sheds light on the infrequent manifestation of clear cell sarcoma within the pancreas but also underscores the pivotal role of vigilant postoperative follow-up in addressing this rare sarcoma. The emphasis on postoperative care serves as a crucial aspect of the broader narrative, acknowledging the need for ongoing monitoring and management to ensure a comprehensive and successful treatment trajectory for patients with this unique presentation of clear cell sarcoma.