Low-grade endometrial stromal sarcoma (LG-ESS) can present diagnostic challenges, due to its overlapping morphological features with other uterine mesenchymal tumors. Misdiagnosis rates remain significant, and immunohistochemical data for LG-ESS are limited to small series and inconsistent antibody panels. This study aimed to refine the IHC profile of LG-ESS by analyzing a large, molecularly confirmed series of 147 cases using a panel of 24 antibodies, including newer markers like transgelin and smoothelin. CD10 and IFITM1, key endometrial stromal markers, were expressed in 86% (92% of those extensively) and 69% (60% of those extensively) of cases, with fusion-positive tumors showing significantly higher expression. Smooth muscle markers (α-SMA, desmin, h-caldesmon, calponin, transgelin) were variably expressed, predominantly in focal or low-intensity patterns, with α-SMA reaching the highest frequency of expression (44%). However, the intensity of smooth muscle marker expression was usually very low. Smoothelin was rarely expressed. Hormone receptors were frequently positive, with PR showing a higher frequency (92% vs. 83%) and intensity than ER. Markers like S-100, HMB45, and CD117 were largely negative; all tumors were p53 wild-type, with preserved SMARCB1/SMARCA4 expression and ALK and ROS1 negativity. This work represents the largest molecularly validated IHC study on LG-ESS, providing a robust diagnostic profile for routine pathology. By addressing key diagnostic limitations and examining newer markers, our study supports a more standardized approach to diagnosing LG-ESS and underscores the value of immunohistochemical panels, particularly in fusion-negative tumors where diagnosis relies on morphological and immunohistochemical interpretation. These findings contribute critical data for improving diagnostic accuracy.

• Klíčová slova
• Endometrial stromal markers, Immunohistochemistry, LG-ESS, Low-grade endometrial stromal sarcoma, Smoothelin,
• MeSH
• dospělí MeSH
• endometriální stromální sarkom * patologie   diagnóza   genetika   chemie   MeSH
• imunohistochemie * metody   MeSH
• lidé středního věku MeSH
• lidé MeSH
• nádorové biomarkery * analýza   MeSH
• nádory endometria * patologie   diagnóza   genetika   chemie   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• stupeň nádoru MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• nádorové biomarkery * MeSH

Uterine sarcomas with KAT6B/A::KANSL1 fusion represent a new entity characterized by bland morphology, commonly with hybrid features of low-grade endometrial stromal sarcoma (LG-ESS) and tumors with smooth muscle differentiation. In our study, we performed a detailed morphological, immunohistochemical, and molecular analysis of 9 cases of these tumors. Six of those had been originally diagnosed as LG-ESS, one as leiomyoma, one as leiomyosarcoma, and the remaining case as sarcoma with the KAT6B/A::KANSL1 fusion. Seven cases showed overlapping features between endometrial stromal and smooth muscle tumors, one case resembled cellular leiomyoma, and one case resembled high-grade endometrial stromal sarcoma. Immunohistochemically, the tumors showed a common expression of smooth muscle markers and endometrial stromal markers. Molecular findings showed the KAT6B/A::KANSL1 fusion in all cases (by NGS and FISH). In addition, mutations affecting genes such as TP53, PDGFRB, NF1, RB1, PTEN, ATM, RB1, FANCD2, and TSC1 were present in all 5 cases with aggressive behavior. One patient with no evidence of disease showed no additional mutations, while another harbored a mutation of a single gene (ERCC3). Of the 8 patients with available follow-up, two died of disease, 3 are currently alive with disease, and 3 have no evidence of disease. The correct recognition of tumors with the KAT6B/A::KANSL1 fusion is essential because despite the bland morphological features of most cases, these tumors have a propensity for aggressive behavior.

• Klíčová slova
• Endometrial stromal sarcoma, KAT6B/A::KANSL1 fusion, Next generation sequencing, Uterine tumor,
• MeSH
• dospělí MeSH
• endometriální stromální sarkom * genetika   patologie   MeSH
• fúze genů MeSH
• fúzní onkogenní proteiny * genetika   MeSH
• histonacetyltransferasy * genetika   MeSH
• imunohistochemie MeSH
• lidé středního věku MeSH
• lidé MeSH
• nádorové biomarkery * genetika   analýza   MeSH
• nádory dělohy * genetika   patologie   MeSH
• nádory endometria genetika   patologie   MeSH
• sarkom * genetika   patologie   MeSH
• senioři MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• fúzní onkogenní proteiny * MeSH
• histonacetyltransferasy * MeSH
• KAT6B protein, human MeSH Prohlížeč
• nádorové biomarkery * MeSH

Three main uterine leiomyoma molecular subtypes include tumors with MED12 mutation, molecular aberrations leading to HMGA2 overexpression, and biallelic loss of FH. These aberrations are mutually exclusive and can be found in approximately 80-90% of uterine leiomyoma, in which they seem to be a driver event. Approximately 10% of uterine leiomyoma, however, does not belong to any of these categories. Uterine leiomyoma with HMGA2 overexpression is the most common subtype in cellular and second most common category of usual leiomyoma. In some of these tumors, rearrangement of HMGA2 gene is present. The most common fusion partner of HMGA2 gene is RAD51B. Limited data suggests that RAD51B fusions with other genes may be present in uterine leiomyoma. In our study, we described two cases of uterine leiomyoma with RAD51B::NUDT3 fusion, which occur in one case of usual and one case of highly cellular leiomyoma. In both cases, no other driver molecular aberrations were found. The results of our study showed that RAD51::NUDT3 fusion can occur in both usual and cellular leiomyoma. RAD51B may be a fusion partner of multiple genes other than HMGA2 and HMGA1. In these cases, RAD51B fusion seems to be mutually exclusive with other driver aberrations defining molecular leiomyoma subtypes. RAD51B::NUDT3 fusion should be added to the spectrum of fusions which may occur in uterine leiomyoma, which can be of value especially in cellular leiomyoma in the context of differential diagnosis against endometrial stromal tumors.

• Klíčová slova
• RAD51B::NUDT3 fusion, Cellular leiomyoma, Uterine leiomyoma,
• MeSH
• DNA vazebné proteiny * genetika   MeSH
• dospělí MeSH
• fúzní onkogenní proteiny genetika   MeSH
• leiomyom * genetika   patologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• nádorové biomarkery genetika   MeSH
• nádory dělohy * genetika   patologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• Názvy látek
• diphosphoinositol polyphosphate phosphohydrolase MeSH Prohlížeč
• DNA vazebné proteiny * MeSH
• fúzní onkogenní proteiny MeSH
• nádorové biomarkery MeSH
• RAD51B 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

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

We assessed the value of cytokeratin 17 (CK17) expression for the differential diagnosis between primary ovarian mucinous tumors and metastases from the gastrointestinal tract (GIT) and the significance of CK17 expression in a broad spectrum of primary ovarian tumors with respect to their prognosis. The sample set consisted of 554 primary ovarian tumors and 255 GIT tumors. In the primary ovarian tumors, a higher CK17 expression (in > 10% of tumors cells) was present only in 0-11.4% of all tumors (including mucinous tumors, micropapillary serous borderline tumors, clear cell, endometrioid, and high-grade serous carcinomas). The only exception was low-grade serous carcinoma, where higher CK17 expression was present in 24% of cases. Concerning GIT tumors, the higher levels of CK 17 expression (in > 10% of tumor cells) were observed in the upper GIT tumors (68.5% of pancreatic ductal adenocarcinoma, 61.6% of gallbladder adenocarcinoma, and 46% of gastric adenocarcinoma), which differs substantially not only from most of the primary ovarian tumors, but also from colorectal carcinoma (3.7%; p < 0.001). The results of our study suggest that expression of CK17 can potentially be used as an adjunct marker in differential diagnosis between primary ovarian mucinous tumors and metastases from the upper GIT, but not from colorectal carcinoma. However, in GIT tumors, CK17 can be used in the differential diagnosis between adenocarcinomas of the upper and lower GIT. Statistical analysis did not reveal strong association of CK17 expression with clinicopathological variables or patient outcomes in any primary ovarian tumors.

• Klíčová slova
• Cytokeratin 17, Differential diagnosis, Gastrointestinal tract tumors, Ovarian tumors,
• MeSH
• adenokarcinom * diagnóza   MeSH
• diferenciální diagnóza MeSH
• gastrointestinální nádory * diagnóza   MeSH
• imunohistochemie MeSH
• keratin-17 MeSH
• kolorektální nádory * diagnóza   MeSH
• lidé MeSH
• nádorové biomarkery analýza   MeSH
• nádory slinivky břišní * diagnóza   MeSH
• nádory vaječníků * patologie   MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• keratin-17 MeSH
• nádorové biomarkery MeSH

Epithelioid sarcoma is a rare soft-tissue sarcoma typically presenting itself as a subcutaneous or deep dermal mass in distal portions of the extremities of adolescents and young adults. They are frequently mistaken for ulcers, abscesses, or infected warts resistant to standard medical treatment. Patients often develop multiple local recurrences with subsequent metastases. We report a case of a 66-year-old patient with chronic leg ulcer who died of generalization of an epithelioid sarcoma.

• Klíčová slova
• Epithelioid sarcoma, chronic ulcer, leg ulcer, peripheral artery disease,
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH

We report a case of a 49-year-old female with desmoplastic small round cell tumor of the uterus (DSRCT). Histologically, in some areas the tumor showed typical features with ample desmoplastic stroma, while in other areas the tumor cells diffusely infiltrated myometrium with only focal desmoplastic reaction. Immunohistochemically, the tumor cells showed diffuse positivity for desmin, CD56, CD57, EMA and cyclin D1. Focal positivity was present for antibodies against cytokeratin AE1/3, BerEP4, NSE, IFITM1 and CD10. The WT-1 antibody (against the N-terminus) showed cytoplasmic positivity in some tumor cells, while the nuclei were negative. P53 expression was wild-type. The Ki-67 index (MIB1 antibody) was about 55%. Other markers examined including transgelin, myogenin, synaptophysin, chromogranin, h-caldesmon, PAX8, and CD117 were all negative. NGS analysis revealed a fusion transcript of the EWSR1 and WT1 genes. DSRCT of the uterus is a rare neoplasm, as only two cases have been reported so far. However, only one of these cases was examined molecularly with a confirmation of the characteristic EWSR1-WT1 fusion. We report a second case of molecularly confirmed DSRCT of the uterus and discuss its clinical features, differential diagnosis and the significance of molecular testing.

• Klíčová slova
• EWSR1-WT1 fusion, desmoplastic small round cell tumor, uterus,
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH