AIMS: Spindle-cell/sclerosing rhabdomyosarcomas (SS-RMS) are clinically and genetically heterogeneous. They include three well-defined molecular subtypes, of which those with EWSR1/FUS::TFCP2 rearrangements were described only recently. This study aimed to evaluate five new cases of SS-RMS and to perform a clinicopathological and statistical analysis of all TFCP2-rearranged SS-RMS described in the English literature to more comprehensively characterize this rare tumour type. METHODS AND RESULTS: Cases were retrospectively selected and studied by immunohistochemistry, fluorescence in situ hybridization with EWSR1/FUS and TFCP2 break-apart probes, next-generation sequencing (Archer FusionPlex Sarcoma kit and TruSight RNA Pan-Cancer Panel). The PubMed database was searched for relevant peer-reviewed English reports. Five cases of SS-RMS were found. Three cases were TFCP2 rearranged SS-RMS, having FUSex6::TFCP2ex2 gene fusion in two cases and triple gene fusion EWSR1ex5::TFCP2ex2, VAX2ex2::ALKex2 and VAX2intron2::ALKex2 in one case. Two cases showed rhabdomyoblastic differentiation and spindle-round cell/sclerosing morphology, but were characterized by novel genetic fusions including EWSR1ex8::ZBTB41ex7 and PLOD2ex8::RBM6ex7, respectively. In the statistical analysis of all published cases, CDKN2A or ALK alterations, the use of standard chemotherapy and age at presentation in the range of 18-24 years were negatively correlated to overall survival. CONCLUSION: EWSR1/FUS::TFCP2-rearranged SS-RMS is a rare rhabdomyosarcoma subtype, affecting predominantly young adults with average age at presentation 34 years (median 29.5 years; age range 7-86 years), with a predilection for craniofacial bones, rapid clinical course with frequent bone and lung metastases, and poor prognosis (3-year overall survival rate 28%).

• Klíčová slova
• ALK, CDKN2A/B, EWSR1, FUS, MyoD1, PLOD2, RBM6, TFCP2, ZBTB41, epithelioid, intraosseous, molecular genetics, rhabdomyosarcoma, spindle cell,
• MeSH
• dítě MeSH
• DNA vazebné proteiny genetika   MeSH
• dospělí MeSH
• fúze genů MeSH
• hybridizace in situ fluorescenční MeSH
• lidé středního věku MeSH
• lidé MeSH
• lysinhydroxylasa genetika   MeSH
• mladiství MeSH
• mladý dospělý MeSH
• nádorové biomarkery genetika   MeSH
• protein EWS vázající RNA genetika   MeSH
• proteiny vázající RNA genetika   MeSH
• retrospektivní studie MeSH
• rhabdomyosarkom * genetika   patologie   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• transkripční faktory * genetika   MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• DNA vazebné proteiny MeSH
• EWSR1 protein, human MeSH Prohlížeč
• lysinhydroxylasa MeSH
• nádorové biomarkery MeSH
• PLOD2 protein, human MeSH Prohlížeč
• protein EWS vázající RNA MeSH
• proteiny vázající RNA MeSH
• RBM6 protein, human MeSH Prohlížeč
• TFCP2 protein, human MeSH Prohlížeč
• transkripční faktory * MeSH

BACKGROUND: Alveolar soft part sarcoma (ASPS) is a very rare mesenchymal malignancy of uncertain origin. It mostly affects young people, with about a quarter of cases being diagnosed in children. CASE: An 11-year-old girl had a painless subcutaneous "lump" in the left elbow area. Imaging exams revealed a solid soft-tissue intramuscular mass of suspicious appearance. A surgical excision of lesion was performed. The biopsy consisted of a lobular tumor measuring 35 × 20 × 12 mm. Histology revealed an epithelioid-cell population arranged in organoid pseudoalveolar pattern. It immunohistochemically expressed TFE3 and harbored the ASPSCR1:: TFE3 gene fusion. A diagnosis of ASPS was established. Subsequently, a wide re-excision of the scar was performed without microscopic residual tumor. The patient is currently without evidence of local recurrence or metastasis. CONCLUSION: ASPS is considered an aggressive and prognostically unfavorable chemoresistant neoplasm. Children have a better prognosis compared to adults. Early detection of tumor in a localized stage with complete surgical removal remains a mainstay therapeutic option. Due to its tendency to late metastases, a long-term thorough follow-up of the patient is necessary.

• Klíčová slova
• ASPSCR1:: TFE3, alveolar soft part sarcoma,
• MeSH
• alveolární sarkom měkkých tkání * diagnóza   genetika   chirurgie   MeSH
• dítě MeSH
• dospělí MeSH
• fúze genů MeSH
• fúzní onkogenní proteiny MeSH
• lidé MeSH
• mladiství MeSH
• prognóza MeSH
• transkripční faktory BHLH-Zip genetika   MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• Názvy látek
• fúzní onkogenní proteiny MeSH
• transkripční faktory BHLH-Zip MeSH

Since the publication of the 2020 World Health Organization classification of soft tissue and bone tumors, the classification of "fibroblastic" tumors has expanded to include a novel subset of tumors characterized by PRRX1::NCOA1/2 gene fusions. These tumors defy conventional classification and are morphologically distinct, characterized by a multi-nodular growth of bland spindle cells suspended in a myxo-collagenous stroma with mild cytologic atypia, "staghorn-like" vessels, and variable perivascular hyalinization. Mitotic activity is rare, and necrosis is not identified. Herein, we present six additional cases of PRRX1-rearranged mesenchymal tumors, including five cases with PRRX1::NCOA1 fusion and one case with PRRX1::KMT2D fusion. Three cases (3/6, 50%) demonstrated focal co-expression of S100 protein and SOX10, thereby expanding the immunohistochemical profile of this emerging entity. Like prior reported cases, there was no evidence of malignant behavior on short-term follow-up. The novel fusion, PRRX1::KMT2D, further expands the molecular spectrum of this entity and leads to a proposed revision of the provisional nomenclature to "PRRX1-rearranged mesenchymal tumor" to both accommodate non-NCOA1/2 fusion partners and allow for the possibility of partial neural or neuroectodermal differentiation.

• Klíčová slova
• KMT2D, Mesenchymal tumor, NCOA1, PRRX1, Soft tissue, Spindle cell,
• MeSH
• fúze genů MeSH
• homeodoménové proteiny genetika   MeSH
• lidé MeSH
• nádorové biomarkery genetika   MeSH
• nádory kostí * MeSH
• nádory měkkých tkání * genetika   patologie   MeSH
• nádory z pojivové a měkké tkáně * MeSH
• proteiny S100 MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• homeodoménové proteiny MeSH
• nádorové biomarkery MeSH
• proteiny S100 MeSH
• PRRX1 protein, human MeSH Prohlížeč

BACKGROUND: Molecular aberrations occurring in primary ovarian clear cell carcinoma (OCCC) can be of diagnostic, predictive, and prognostic significance. However, a complex molecular study including genomic and transcriptomic analysis of large number of OCCC has been lacking. METHODS: 113 pathologically confirmed primary OCCCs were analyzed using capture DNA NGS (100 cases; 727 solid cancer related genes) and RNA-Seq (105 cases; 147 genes) in order to describe spectra and frequency of genomic and transcriptomic alterations, as well as their prognostic and predictive significance. RESULTS: The most frequent mutations were detected in genes ARID1A, PIK3CA, TERTp, KRAS, TP53, ATM, PPP2R1A, NF1, PTEN, and POLE (51,47,27,18,13,10,7,6,6, and 4%, respectively). TMB-High cases were detected in 9% of cases. Cases with POLEmut and/or MSI-High had better relapse-free survival. RNA-Seq revealed gene fusions in 14/105 (13%) cases, and heterogeneous expression pattern. The majority of gene fusions affected tyrosine kinase receptors (6/14; four of those were MET fusions) or DNA repair genes (2/14). Based on the mRNA expression pattern, a cluster of 12 OCCCs characterized by overexpression of tyrosine kinase receptors (TKRs) AKT3, CTNNB1, DDR2, JAK2, KIT, or PDGFRA (p < 0.00001) was identified. CONCLUSIONS: The current work has elucidated the complex genomic and transcriptomic molecular hallmarks of primary OCCCs. Our results confirmed the favorable outcomes of POLEmut and MSI-High OCCC. Moreover, the molecular landscape of OCCC revealed several potential therapeutical targets. Molecular testing can provide the potential for targeted therapy in patients with recurrent or metastatic tumors.

• Klíčová slova
• Capture DNA NGS, POLE mutation, RNA-Seq, Rare ovarian tumors,
• MeSH
• adenokarcinom z jasných buněk * genetika   MeSH
• fúze genů MeSH
• genomika MeSH
• lidé MeSH
• lokální recidiva nádoru * MeSH
• stanovení celkové genové exprese MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

This article presents 2 cases of TFG::MET-rearranged mesenchymal tumor, an extremely rare molecular subset among an emerging group of mesenchymal neoplasms with kinase gene (NTRK, BRAF, RET and others) alterations. Both tumors were congenital, occurred in female patients and presented as huge masses on the trunk and thigh, measuring 18 and 20 cm in the largest dimension. Both cases showed identical areas with a distinctive triphasic morphology resembling fibrous hamartoma of infancy (FHI), consisting of haphazardly arranged ovoid to spindled cells traversed by variably cellular and hyalinized fascicles admixed with (most likely non-neoplastic) adipose tissue. In other areas, a high-grade infantile fibrosarcoma/malignant peripheral nerve sheath tumor-like (IFS/MPNST-like) morphology was present in both cases. While the first case co-expressed CD34 and S100 protein, the other case did not. When combined with the three previously reported MET-rearranged cases (of which two harbored TFG::MET fusion), 3/5 and 3/4 of MET-rearranged and TFG::MET fusion-associated tumors, respectively exhibited similar triphasic FHI-like low-grade morphology. This points toward the existence of a relatively distinct morphological subset among kinase-fusion-associated tumors which seems to be strongly associated with MET fusions. It seems some of these low-grade cases may transform into a high-grade variant with IFS/MPNST-like morphology as has been observed in other tumors with kinase gene fusions. While most cases seem to follow an indolent clinical course, the recognition of these tumors is clinically relevant as MET tyrosine kinase inhibitors might represent an effective treatment option for clinically aggressive or unresectable cases.

• Klíčová slova
• MET rearrangement, TFG::MET fusion, congenital, fibrous hamartoma of infancy, infantile fibrosarcoma, kinase fusion, lipofibromatosis-like neural tumor, mesenchymal, soft tissues,
• MeSH
• fibrosarkom * genetika   MeSH
• fúze genů MeSH
• lidé MeSH
• nádorové biomarkery genetika   MeSH
• nádory kůže * MeSH
• nádory měkkých tkání * genetika   patologie   MeSH
• nádory z pojivové a měkké tkáně * MeSH
• neurofibrosarkom * MeSH
• proteiny genetika   MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• MET protein, human MeSH Prohlížeč
• nádorové biomarkery MeSH
• proteiny MeSH
• TFG protein, human MeSH Prohlížeč

Chromosomal rearrangements of the human KMT2A/MLL gene are associated with de novo as well as therapy-induced infant, pediatric, and adult acute leukemias. Here, we present the data obtained from 3401 acute leukemia patients that have been analyzed between 2003 and 2022. Genomic breakpoints within the KMT2A gene and the involved translocation partner genes (TPGs) and KMT2A-partial tandem duplications (PTDs) were determined. Including the published data from the literature, a total of 107 in-frame KMT2A gene fusions have been identified so far. Further 16 rearrangements were out-of-frame fusions, 18 patients had no partner gene fused to 5'-KMT2A, two patients had a 5'-KMT2A deletion, and one ETV6::RUNX1 patient had an KMT2A insertion at the breakpoint. The seven most frequent TPGs and PTDs account for more than 90% of all recombinations of the KMT2A, 37 occur recurrently and 63 were identified so far only once. This study provides a comprehensive analysis of the KMT2A recombinome in acute leukemia patients. Besides the scientific gain of information, genomic breakpoint sequences of these patients were used to monitor minimal residual disease (MRD). Thus, this work may be directly translated from the bench to the bedside of patients and meet the clinical needs to improve patient survival.

• MeSH
• akutní lymfatická leukemie * genetika   MeSH
• akutní myeloidní leukemie * genetika   MeSH
• dítě MeSH
• dospělí MeSH
• fúze genů MeSH
• histonlysin-N-methyltransferasa * genetika   MeSH
• kojenec MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• předškolní dítě MeSH
• protoonkogenní protein MLL * genetika   MeSH
• senioři MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• kojenec MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• předškolní dítě MeSH
• senioři MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• histonlysin-N-methyltransferasa * MeSH
• KMT2A protein, human MeSH Prohlížeč
• protoonkogenní protein MLL * MeSH

A focal adenomatoid-microcystic pattern is not uncommon in peritoneal mesothelioma, but tumors composed almost exclusively of this pattern are distinctly rare and have not been well characterized. A small subset of mesotheliomas (mostly in children and young adults) are characterized by gene fusions including EWSR1/FUS::ATF1, EWSR1::YY1, and NTRK and ALK rearrangements, and often have epithelioid morphology. Herein, we describe five peritoneal mesothelial neoplasms (identified via molecular screening of seven histologically similar tumors) that are pure adenomatoid/microcystic in morphology and unified by the presence of an NR4A3 fusion. Patients were three males and two females aged 31-70 years (median, 40 years). Three presented with multifocal/diffuse and two with a localized disease. The size of the individual lesions ranged from 1.5 to 8 cm (median, 4.7). The unifocal lesions originated in the small bowel mesentery and the mesosigmoid. Treatment included surgery, either alone (three) or combined with hyperthermic intraperitoneal chemotherapy (two), and neoadjuvant or adjuvant chemotherapy (one case each). At the last follow-up (6-13 months), all five patients were alive and disease-free. All tumors were morphologically similar, characterized by extensive sieve-like microcystic growth with bland-looking flattened cells lining variably sized microcystic spaces and lacked a conventional epithelioid or sarcomatoid component. Immunohistochemistry confirmed mesothelial differentiation, but most cases showed limited expression of D2-40 and calretinin. Targeted RNA sequencing revealed an NR4A3 fusion (fusion partners were EWSR1 in three cases and CITED2 and NIPBL in one case each). The nosology and behavior of this morphomolecularly defined novel peritoneal mesothelial neoplasm of uncertain biological potential and its distinction from adenomatoid variants of conventional mesothelioma merit further delineation as more cases become recognized.

• Klíčová slova
• EWSR1, NR4A3, adenomatoid tumor, gene fusion, microcystic, peritoneal mesothelioma,
• MeSH
• adenom * MeSH
• DNA vazebné proteiny genetika   MeSH
• dospělí MeSH
• fúze genů MeSH
• lidé středního věku MeSH
• lidé MeSH
• mezenterium patologie   MeSH
• mezoteliom * genetika   MeSH
• nádorové biomarkery genetika   MeSH
• peritoneální nádory * genetika   patologie   MeSH
• proteiny buněčného cyklu genetika   MeSH
• receptory thyreoidních hormonů genetika   MeSH
• represorové proteiny genetika   MeSH
• senioři MeSH
• steroidní receptory * genetika   MeSH
• trans-aktivátory genetika   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• CITED2 protein, human MeSH Prohlížeč
• DNA vazebné proteiny MeSH
• nádorové biomarkery MeSH
• NIPBL protein, human MeSH Prohlížeč
• NR4A3 protein, human MeSH Prohlížeč
• proteiny buněčného cyklu MeSH
• receptory thyreoidních hormonů MeSH
• represorové proteiny MeSH
• steroidní receptory * MeSH
• trans-aktivátory MeSH

BACKGROUND: Clear cell (hemangioblastoma-like) stromal tumor of the lung (CCSTL) is a rare pulmonary neoplasm. Recently, 9 cases of CCSTL harboring the YAP1-TFE3 gene fusion have been described, and it has been suggested that this aberration could be a characteristic feature of this tumor. CASE PRESENTATION: We here report another case of CCSTL in a 57-year-old male, which presented as a solitary lung nodule 45 mm in the greatest dimension. Microscopically, the tumor consisted of epithelioid to spindled cells with mild-to-moderate nuclear atypia, finely granular or vesicular chromatin, and small nucleoli. Nuclear indentations were a common finding. There were up to 3 mitoses per 10 HPF. The cytoplasm was slightly eosinophilic or clear. Scattered non-tumor large multinucleated cells were present. Immunohistochemically, the tumor cells showed diffuse positivity for TFE3, CD10, vimentin, and IFITM1. Other markers examined were negative, and the expression of lineage-specific markers was not found. NGS analysis revealed a fusion transcript of the YAP1 and TFE3 genes, and a pathogenic variant of the MUTYH gene. CONCLUSION: Our finding supports the recent data suggesting that CCSTL represents a distinct entity characterized by the recurrent YAP1-TFE3 fusion.

• Klíčová slova
• Clear cell (hemangioblastoma-like) stromal tumor, Lung, YAP1-TFE3 fusion,
• MeSH
• fúze genů MeSH
• lidé středního věku MeSH
• lidé MeSH
• nádorové biomarkery genetika   analýza   MeSH
• nádory plic * genetika   MeSH
• obrovské buňky chemie   MeSH
• plíce MeSH
• transkripční faktory BHLH-Zip * genetika   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• Názvy látek
• nádorové biomarkery MeSH
• TFE3 protein, human MeSH Prohlížeč
• transkripční faktory BHLH-Zip * MeSH

BACKGROUND: Biphenotypic sinonasal sarcoma (BFSS) is a topographically specific low-grade sarcoma that was first described only 10 years ago. The term biphenotypic comes from the co-expression of markers of muscle differentiation and neural crest that is characteristic for this tumor. CASE: A 78-year-old woman manifested with prolonged breathing difficulties through the left nasal passage. Rhinoendoscopy and CT scans showed an obturation of the middle and posterior part of the left nasal cavity by a polypoid tumor mass with a stalk in the ethmoid sinus. It spread into the nasopharynx. The tumor was resected and extracted from the nasopharynx through the oral cavity. Grossly, it was a compact polyp measuring 6 × 3,5 × 3cm. Histology revealed a uniform neoplastic spindle cell population arranged in a fascicular pattern. It expres-sed S100 protein, smooth muscle actin, calponin and muscle-specific actin. Molecular genetic analysis of the tissue showed PAX3:: MAML3 gene fusion. The findings confirmed a dia-gnosis of BFSS. CONCLUSION: BFSS is a very rare, locally aggressive malignant tumor without metastatic potential. In contrast to other malignancies in a given locality, it possesses a relatively favorable prognosis. In bio-psy practice, the pathologists knowledge of this unique histopathological entity is principal because it should be always considered when encountering a low-grade spindle cell neoplasia arising in the sinonasal region.

• Klíčová slova
• PAX3::MAML3, S100 protein, biphenotypic sinonasal sarcoma, smooth muscle actin,
• MeSH
• aktiny MeSH
• fúze genů MeSH
• lidé MeSH
• nádory měkkých tkání * MeSH
• sarkom * genetika   MeSH
• senioři MeSH
• Check Tag
• lidé MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• Názvy látek
• aktiny MeSH

Epithelioid fibrous histiocytoma (EFH) is a distinctive cutaneous neoplasm with a relatively variable morphological appearance. Recently, it has been shown that this tumor is molecularly characterized by ALK gene fusions. We report three EFHs with unusual histological presentation represented by a prominent/predominant spindle cell proliferation arranged in a variably storiform/whirling architectural pattern with or without stromal sclerosis. One of the cases closely resembled cellular fibrous histiocytoma. All three cases were immunohistochemically ALK-positive and were analyzed for ALK gene rearrangements using a next-generation sequencing-based assay (FusionPlex Sarcoma Kit, ArcherDx). Three novel fusions, namely AP3D1::ALK, COL1A::ALK, and LRRFIP2::ALK, were detected and further confirmed by FISH in all 3 cases and RT-PCR in 1 case. All patients were elderly (62-63 years) and presented with a solitary polypoid lesion on the extremities. The awareness of these morphological variants is important since it entertains a wide and slightly different differential diagnosis than conventional EFH. We also presented evidence that a clear separation of EFH from BFH in all cases may not be as straightforward as previously thought. The consistent ALK immunoexpression and the continually expanding scale of ALK gene rearrangements provide a useful tool to distinguish EFH from its histologic mimics.

• Klíčová slova
• ALK fusion, Epithelioid fibrous histiocytoma, Spindle cell, Storiform, Stromal sclerosis,
• MeSH
• benigní fibrózní histiocytom * diagnóza   genetika   patologie   MeSH
• fúze genů MeSH
• lidé středního věku MeSH
• lidé MeSH
• nádory měkkých tkání * patologie   MeSH
• sarkom * patologie   MeSH
• tyrosinkinasové receptory genetika   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• ALK protein, human MeSH Prohlížeč
• tyrosinkinasové receptory MeSH