OBJECTIVE: Targeted therapy in translocation-associated sarcomas has been limited to oncogenic activation of tyrosine kinases or ligands while gene fusions resulting in aberrant expression of transcription factors have been notoriously difficult to target. Moreover, secondary genetic alterations in sarcomas driven by translocations are uncommon, comprising mostly alterations in tumor suppressor genes (TP53, CDKN2A/B). Our study was triggered by an index patient showing a dramatic clinical response by targeting the secondary BRAF V600E mutation in a metastatic angiomatoid fibrous histiocytoma (AFH) harboring the typical EWSR1::CREB1 fusion.
METHODS: The patient, a 28-year-old female, was diagnosed with an AFH of the thigh and followed a highly aggressive clinical course, with rapid multifocal local recurrence within a year and widespread distant metastases (adrenal, bone, liver, lung). The tumor showed characteristic morphologic features, with histiocytoid cells intermixed with hemorrhagic cystic spaces and lymphoid aggregates. In addition to the pathognomonic EWSR1::CREB1 fusion, targeted DNA sequencing revealed in both primary and adrenal metastatic sites a hot spot BRAF V600E mutation and a CDKN2A/B deletion. Accordingly, the patient was treated with a BRAF-MEK inhibitor combination (encorafenib/binimetinib) showing an excellent but short-lived response.
RESULTS: Using a CRISPR-Cas9 approach, we introduced the BRAF c.1799 T>A point mutation in human embryonic stem (hES) cells harboring a conditional EWSR1 (exon7)::CREB1 (exon7) translocation and further differentiated to mesenchymal progenitors (hES-MP) before fusion expression. The cells maintained the fusion transcript expression and the AFH core gene signature while responding to treatment with encorafenib and binimetinib.
CONCLUSIONS: These results highlight that additional targeted DNA NGS in chemotherapy-resistant translocation-associated sarcomas may reveal actionable oncogenic drivers occurring as secondary genetic events during disease progression.

Angiomatoid fibrous histiocytoma (AFH) is a borderline tumor usually affecting the the children or young adults. 18F-Fluorodexoyglucose (FDG) positron emission tomography/computed tomography (PET/CT) investigations of pulmonary AFH are rare, and there are currently no reports of intense FDG uptake in AFH.
We report an AFH that occurred in the lung of a 57-year-old woman. She presented with paroxysmal cough and occasional bloodshot sputum. 18FFDG PET/CT revealed a right parahilar nodule with intense FDG-avidity, middle lobe atelectasis, and several bilateral axillary lymph nodes with mild hypermetabolic activity. This patient underwent a right middle lobe lobectomy via video-assisted thoracoscopy. Histopathologically, the diagnosis was pulmonary AFH. She had an uneventful postoperative course, and the bilateral axillary lymph nodes regressed during postoperative follow-up.
The clinical presentation and image findings of patients with primary pulmonary AFH may be potential diagnosis pitfalls. The diagnosis of lymph nodes or distant metastases should be approached with caution. To avoid misdiagnosis, biopsy with histological examination and immunohistochemichal staining should be performed as early as possible.

目的： 探讨血管瘤样纤维组织细胞瘤的临床病理学及分子特征。 方法： 收集河南省儿童医院病理科2018—2022年血管瘤样纤维组织细胞瘤5例，总结分析临床特点、组织学及免疫组织化学结果，荧光原位杂交（FISH）及荧光PCR-毛细管电泳测序法检测相应基因改变并随访。 结果： 5例患儿中，男患儿3例，女患儿2例，年龄3~10岁。发病部位1例位于腋窝淋巴结区域，余4例位于皮下软组织。临床表现为进展缓慢的无痛性肿块，超声显示低回声包块，均予手术完整切除送病理检查。肿瘤最大径1.0~3.5 cm，切面灰白、质中，实性或囊性。组织学肿瘤均有纤维性包膜及淋巴细胞增生、聚集。肿瘤细胞梭形或卵圆形，编织状或弥漫片状分布，4例中可见核分裂象。囊性区未见上皮衬覆，囊内可见大量红细胞或片状坏死。免疫组织化学染色显示5例均表达结蛋白，4例表达CD99及平滑肌肌动蛋白（SMA），1例表达间变性淋巴瘤激酶（ALK，D5F3），Ki-67阳性指数4例约5%，1例约40%。FISH检测结果提示5例均存在EWSR1基因断裂，其中4例同时伴有CREB1基因断裂，表达ALK（D5F3）蛋白的病例不存在ALK基因断裂及突变。3例获随访资料，随访6~60个月，均未复发。 结论： 血管瘤样纤维组织细胞瘤属儿童罕见的中间型间叶源性肿瘤，常发生在头颈部、四肢躯干皮下软组织，病理形态多样，免疫表型常表达结蛋白、SMA及CD99，分子检测有助于明确诊断。偶见ALK蛋白表达。.

Objective: To investigate the clinical application of EWSR1 gene rearrangement by fluorescence in situ hybridization (FISH) in bone and soft tissue tumors and to analyze the cases with atypical signal pattern. Methods: The cases detected for EWSR1 gene rearrangement by FISH in Beijing Jishuitan Hospital, Capital Medical University from 2014 to 2021 were collected, and the value of detecting EWSR1 gene rearrangement for diagnosing bone and soft tissue tumors was analyzed. The cases with atypical positive signals were further analyzed by next generation sequencing (NGS). Results: FISH using EWSR1 break-apart probe kit was successfully performed in 97% (205/211) of cases, 6 cases failed. Four of the 6 failures were due to improper decalcification, 1 case due to signal overlap caused by thick slices, and 1 case due to signal amplification and disorder. EWSR1 gene rearrangements were positive in 122 cases (122/205, 59%), atypical positive signal in 8 cases (8/205, 4%), and negative in 75 cases (75/205, 37%). In cases testing positive, the percentage of positive cells ranged from 34% to 98%, with 120 cases (120/122, 98%) showing a positive cell percentage greater than 50%. Among the 205 successfully tested cases, 156 cases were histologically diagnosed as Ewing\'s sarcoma, of which 110 were positive (110/156, 71%), 7 were atypical positive (7/156, 4%), and 39 were negative (39/156, 25%). Nine cases were histologically diagnosed as clear cell sarcoma of soft tissue, of which 6 were positive (6/9), 1 was atypical positive (1/9), and 2 were negative (2/9). Five cases were histologically diagnosed as extraskeletal myxoid chondrosarcoma, of which 2 were positive (2/5) and 3 were negative (3/5). Three cases were histologically diagnosed as angiomatoid fibrous histiocytoma, of which 2 were positive (2/3) and 1 was negative (1/3). Two cases were histologically diagnosed as myoepithelioma of soft tissue, of which 1 was positive (1/2) and 1 was negative (1/2). One case was histologically diagnosed as olfactory neuroblastoma with a positive result. The 29 other tumor cases including osteosarcoma, synovial sarcoma, and malignant melanoma and others were all negative. Basing on histology as the standard for diagnosis and considering atypical positive cases as negative, comparing with the 29 cases of other tumors as control group, the sensitivity for diagnosing Ewing\'s sarcoma through the detection of EWSR1 gene rearrangement was 71%, and the specificity was 100%; the sensitivity for diagnosing clear cell sarcoma of soft tissue was 67%, and the specificity was 100%; the sensitivity for diagnosing extraskeletal myxoid chondrosarcoma was 40%, and the specificity was 100%; the sensitivity for diagnosing angiomatoid fibrous histiocytoma was 67%, and the specificity was 100%; the sensitivity for diagnosing myoepithelioma of soft tissue was 50%, and the specificity was 100%; the sensitivity for diagnosing olfactory neuroblastoma was 100%, and the specificity was 100%. Four of 8 cases with atypical positive signals analyzed by NGS showed EWSR1 rearrangement, including EWSR1::FLI1 in one case of Ewing sarcoma, EWSR1::NFATC2 in one case of EWSR1::NFATC2-rearranged sarcoma, EWSR1::ATF1 in one case of clear cell sarcoma of soft tissue and EWSR1::NR4A3 in one case of extraskeletal myxoid chondrosarcoma. Conclusions: Detection of EWSR1 rearrangement by FISH is of utmost significance in the diagnosis of bone and soft tissue tumors. Cases with atypical positive signals should be further scrutinized, correlating with their histomorphology and verifying by NGS if necessary.
目的： 探讨应用荧光原位杂交（FISH）检测骨与软组织肿瘤EWSR1基因重排的临床应用价值并对出现不典型信号的病例进行分析。 方法： 收集首都医科大学附属北京积水潭医院2014—2021年应用FISH检测EWSR1基因重排的病例，分析其用于诊断相关骨与软组织肿瘤的临床应用价值并对FISH检测结果呈不典型信号的病例进行二代测序以进一步分析。 结果： 应用FISH检测EWSR1基因重排病例211例，检测成功205例（205/211，97%），失败6例（6/211，3%）。6例检测失败病例中，4例因骨组织脱钙不当未检测到荧光信号，1例因切片太厚信号重叠无法判读，1例因信号扩增且杂乱无法判读。205例检测成功病例中，阳性122例（122/205，59%），不典型阳性8例（8/205，4%），阴性75例（75/205，37%）。阳性者其阳性细胞百分数为34%~98%，其中120例（120/122，98%）阳性细胞百分数>50%。205例检测成功病例中，156例组织学诊断为尤因肉瘤，其中阳性110例（110/156，71%），不典型阳性7例（7/156，4%），阴性39例（39/156，25%）。9例组织学诊断为软组织透明细胞肉瘤，其中阳性6例（6/9），不典型阳性1例（1/9），阴性2例（2/9）。5例组织学诊断为骨外黏液样软骨肉瘤，其中阳性2例（2/5），阴性3例（3/5）。3例组织学诊断为血管瘤样纤维组织细胞瘤，其中阳性2例（2/3），阴性1例（1/3）。2例组织学诊断为软组织肌上皮瘤，其中阳性1例（1/2），阴性1例（1/2）。1例组织学诊断为嗅神经母细胞瘤，结果为阳性。检测其他肿瘤29例，包括骨肉瘤、滑膜肉瘤、恶性黑色素瘤等，均为阴性。以组织学为金标准，将不典型阳性按阴性考虑，以29例其他肿瘤为对照组病例，检测EWSR1基因重排诊断尤因肉瘤的灵敏度为71%，特异度为100%；诊断软组织透明细胞肉瘤的灵敏度为67%，特异度为100%；诊断骨外黏液样软骨肉瘤的灵敏度为40%，特异度为100%；诊断血管瘤样纤维组织细胞瘤的灵敏度为67%，特异度为100%；诊断软组织肌上皮瘤的灵敏度为50%，特异度为100%；诊断嗅神经母细胞瘤的灵敏度为100%，特异度为100%。8例具有不典型阳性信号的病例中4例有足够组织材料送检二代测序，结果均证实存在EWSR1基因重排，形成的融合基因分别为EWSR1：：FLI1（尤因肉瘤）、EWSR1：：NFATC2（EWSR1：：NFATC2肉瘤）、EWSR1：：ATF1（软组织透明细胞肉瘤）和EWSR1：：NR4A3（骨外黏液样软骨肉瘤）。 结论： 应用FISH检测EWSR1基因重排对骨与软组织肿瘤的诊断具有重要意义。对于出现不典型信号病例的解读要紧密结合组织形态，必要时应用其他分子检测方法验证。.

UNASSIGNED: Bisherige Arbeiten haben gezeigt, dass Hydrochlorothiazid (HCT) aufgrund seiner photokarzinogenen Wirkung einen Risikofaktor für Plattenepithelkarzinome (SCC) und Basalzellkarzinome (BCC) darstellt. Atypische Fibroxanthome (AFX) und pleomorphe dermale Sarkome (PDS), beides UV‐induzierte Tumoren, stellen eine seltene, aber zunehmende Tumorentität der Haut dar. In dieser Studie soll untersucht werden, ob die Einnahme von HCT bei Patienten mit AFX/PDS höher ist als bei Patienten mit SCC/BCC und ob dies ein Risikofaktor für die Entwicklung von AFX/PDS sein könnte.
UNASSIGNED: In einer retrospektiven Studie an vier deutschen Hautkrebszentren wurden AFX/PDS‐Fälle und SCC/BCC‐Kontrollen über einen Zeitraum von sieben Jahren (2013‐2019) geschlechts‐ und alters‐gematcht (1:3) auf die Einnahme von HCT und immunsuppressiven Medikamenten sowie auf Zweitmalignome und Diabetes mellitus untersucht.
UNASSIGNED: Insgesamt wurden 146 AFX/PDS und 438 Kontrollen (SCC/BCC) in die Studie eingeschlossen. Die Einnahme von HCT war bei Patienten mit AFX/PDS (44,5%) im Vergleich zu Patienten mit SCC/BCC (25,3%) signifikant häufiger. Außerdem war Diabetes mellitus bei AFX/PDS‐Patienten signifikant häufiger.
UNASSIGNED: Diese Studie zeigt eine signifikant höhere Einnahme von HCT bei Patienten mit AFX/PDS im Vergleich zu SCC/BCC. Dies legt nahe, dass HCT ein Risikofaktor für AFX/PDS sein könnte. Darüber hinaus könnten ein Diabetes mellitus oder dessen Begleiterkrankungen mit einem erhöhten Risiko für AFX/PDS assoziiert sein.

OBJECTIVE: Previous work has demonstrated that hydrochlorothiazide (HCTZ) is a risk factor for squamous cell carcinomas (SCC) and basal cell carcinomas (BCC) due to pro-photocarcinogenic effects. Atypical fibroxanthoma (AFX) and pleomorphic sarcoma (PDS), both ultraviolet-induced cancers, display a rare but rising cutaneous tumor entity. This study aimed to evaluate if the use of HCTZ is higher in patients with AFX/PDS than in patients with SCC/BCC and subsequently may be a risk factor for AFX/PDS-development.
METHODS: In a retrospective study of four German skin cancer centers, AFX/PDS cases and SCC/BCC controls were sex and age matched (1:3) over a time-period of 7 years (2013-2019) to evaluate the use of HCTZ, immunosuppressive medication, second malignancies, and presence of diabetes mellitus.
RESULTS: Overall, 146 AFX/PDS and 438 controls (SCC/BCC) were included in the study. The use of HCTZ was significantly higher in patients with AFX/PDS (44.5%) compared to patients with SCC/BCC (25.3%). Additionally, the presence of diabetes mellitus was significantly higher in AFX/PDS patients.
CONCLUSIONS: This study demonstrates a significantly higher use of HCTZ in patients with AFX/PDS compared to SCC/BCC. This result suggests that HCTZ may be a risk factor for AFX/PDS. Additionally, diabetes mellitus or its comorbidities may be associated with an increased risk for AFX/PDS.

Primary pulmonary myxoid sarcoma (PPMS) and thoracic angiomatoid fibrous histiocytoma (AFH) are rare neoplasms with EWSR1 fusions and overlapping morphology. Both tumor types often show epithelial membrane antigen expression, but AFH characteristically co-expresses desmin. We encountered a case of PPMS with the unexpected finding of patchy, strong anaplastic lymphoma kinase (ALK) (previously reported in AFH) and synaptophysin expression. We evaluated a cohort of PPMS and thoracic AFH with systematic morphologic comparison and surveyed for aberrant expression of ALK and synaptophysin. Medical records and slides were reviewed for 16 molecularly confirmed cases of PPMS (n=5) and thoracic AFH (n=11). Each case was scored for morphologic characteristics typical of PPMS and/or AFH. ALK, synaptophysin, chromogranin, desmin, and epithelial membrane antigen immunostains were performed on cases with available tissue. AFH and PPMS cases showed similar age at presentation and long-term tumor behavior. Almost all cases of PPMS and AFH had a fibrous pseudocapsule and lymphoid rim. All PPMS had myxoid stroma and reticular growth pattern, but these features were also present in a subset of AFH. Synaptophysin expression was present in 6 of 11 AFH and 1 of 5 PPMS; all tested cases were negative for chromogranin (n=15). One case of AFH and 1 case of PPMS showed focally strong coexpression of synaptophysin and ALK. AFH and PPMS show considerable clinicopathologic overlap. When supportive, the immunohistochemical findings described may aid in diagnosis before molecular confirmation. PPMS and AFH may be morphologic variants of the same clinicopathologic entity, which can show more immunophenotypic variability than previously reported.

Several high-grade pleomorphic sarcoma cases that cannot be classified into any existing established categories have been reported. These cases were provisionally classified into undifferentiated pleomorphic sarcoma (UPS). Some dedifferentiated liposarcoma (DDLS) cases may also have been classified into the UPS category due to the absence of MDM2 amplification or an atypical lipomatous tumor/well-differentiated liposarcoma component. We retrieved and reviewed 77 high-grade pleomorphic sarcoma cases, initially diagnosed as UPS in 66 cases and DDLS in 11 cases. Fluorescence in situ hybridization (FISH) analyses of DDIT3 and MDM2 were performed for available cases. Of the cases successfully subjected to DDIT3 FISH (n = 56), nine (7 UPS and 2 DDLS) showed DDIT3 amplification but no MDM2 amplification. Two UPS cases showed both telomeric (5\') and centromeric (3\') amplification of DDIT3 or low polysomy of chromosome 12, whereas 5 UPS and 2 DDLS cases showed 5\'-predominant DDIT3 amplification. Histopathologically, all cases showed UPS-like proliferation of atypical pleomorphic tumor cells. Immunohistochemically, only one case showed focal nuclear positivity for DDIT3, supporting the previous finding that DDIT3 expression was not correlated with DDIT3 amplification. All three cases with focal MDM2 expression involved 5\'-predominant amplification, two of which showed DDLS-like histological features. The majority of cases (7/9) showed decreased expression in p53 staining, suggesting that DDIT3 amplification regulates the expression of TP53 like MDM2. From a clinicopathological perspective, we hypothesize that DDIT3-amplified sarcoma, especially with 5\'-predominant amplification, can be reclassified out of the UPS category.

UNASSIGNED: Undifferentiated Pleomorphic Sarcoma (UPS) is a common soft tissue sarcoma that can develop in various organs, but lung involvement is usually due to metastasis. UPS originating primarily in the lungs is called primary pulmonary undifferentiated pleomorphic Sarcoma (PPUPS) and is exceptionally rare. It is a high-grade pleomorphic neoplasm with no identifiable lines of differentiation. Thus, it is essentially a diagnosis of exclusion that requires extensive clinical, radiographic and histopathological evaluation. Herein we report the case of a 49-year-old gentleman who presented with anemia and weight loss and was found to have a large right lung mass. The lesion was diagnosed as PPUPS after detailed histopathological, immunohistochemical and molecular analysis and exclusion of a possible extrapulmonary origin.

Myxofibrosarcoma (MFS) is a malignant fibroblastic/myofibroblastic neoplasm with a prominent myxoid area. It has the clinical features of frequent local recurrence (LR) and occasional distant metastasis. Robust epidemiological data on MFS in China are lacking. The aim of this retrospective analysis was to determine the natural history of MFS, identify prognostic factors for recurrence and describe the real-life outcomes of MFS. We reviewed 52 patients with primary MFS from the First Affiliated Hospital of Nanjing Medical University diagnosed between 2016 and 2020. All tumors were subjected to retrospective univariate analysis for prognostic factors of the disease, including tumor size, grade, location and sex; patient age; planned operation; surgical margin; and laboratory results. The significant factors identified by univariate analysis were subsequently analyzed via multivariate analysis. Overall survival (OS), post-treatment LR and metastatic-free survival were assessed as outcomes. The median age was 61 years (range, 13-93). Fourteen (26.92%) patients exhibited low grade disease, and 38 (73.08%) exhibited high grade disease. Among the 29 males, and 23 females, 15 (28.85%) had tumors in the trunk, 37 (71.15%) had tumors in the extremities, 26 had undergone planned surgery, and 26 had unexpected unplanned operation. The margin was negative in 39 (75%) patients and positive in 13 patients (25%). The serum creatine kinase (CK) concentration was high level in 33 (63.46%) patients and low level in 19 (36.54%) patients. The serum lactate dehydrogenase (LDH) levels were low in 23 (44.23%) patients and high in 29 (55.77%) patients. LR was observed in 25 patients (48.08%), and 4 patients developed metastasis. A worse LR rate was found for patients with a low CK level (84.21%) than for those with a high CK level (27.27%) at 5 years (p < 0.05). The LR rate of patients who underwent planned surgery was lower than that of patients who underwent unplanned surgery (p < 0.05). There were significantly more patients with positive margins than patients with negative margins (92.30%, and 33.33%, respectively; p < 0.05). Moreover, superficial tumors were also associated with greater recurrence rate (2/20 [10%]) than deep tumors, (23/32 [71.86%]) [p < 0.05]. The probability of LR in patients with MFS was significantly greater in association with unplanned operations, positive margins, low serum CK levels or superficial tumor depth. These data could help identify high-risk patients; thus, more careful follow-up should be performed for higher-risk patients. Diagnosis and treatment at qualified regular medical centers can reduce the local recurrence rate of MFS.