Objective:To investigate the clinicopathological features, immunophenotype, molecular characteristics, and differential diagnosis of primary intracranial DICER1-mutant sarcoma in order to better understand this tumor type.Methods:A retrospective analysis was conducted on 7 cases of primary intracranial DICER1-mutant sarcoma diagnosed in the Department of Pathology, Sun Yat-sen University Cancer Center, Guangzhou, China between 2021 and 2023 using next-generation sequencing. At the same time, 10 gliosarcomas, 4 intracranial FET::CREB fusion-positive mesenchymal tumors, 4 malignant meningiomas, 3 malignant solitary fibrous tumors, 3 malignant peripheral nerve sheath tumors, 3 synovial sarcomas and 3 rhabdomyosarcomas (total 30 cases) were selected as control.Results:Among the 7 patients with primary intracranial DICER1-mutant sarcoma, 6 were male and 1 was female, aged 10-32 years (median, 23 years). The tissue morphology was predominantly spindle or pleomorphic sarcoma-like, with 6 cases exhibiting eosinophilic globules, and 3 cases showing rhabdomyoblastic or rhabdomyosarcoma-like cell differentiation. Immunohistochemistry revealed focal desmin expression in 3 cases (3/7), ATRX loss in 3 cases (3/7), and p53 mutant pattern in 4 cases (4/7). Additionally, 4 cases (4/7) showed focal or diffuse SALL4 expression, whereas the control cases (30 cases) did not exhibit SALL4 protein expression, suggesting that SALL4 may possess certain auxiliary diagnostic value. Next-generation sequencing confirmed that all 7 cases of primary intracranial DICER1-mutant sarcoma harbored mutations in the DICER1 gene, with 5 cases having the mutation site at p.E1813D. Until May 2024, all 7 patients were alive.Conclusions:Primary intracranial DICER1-mutant sarcoma is a rare tumor. Understanding its morphological characteristics, immunohistochemical and molecular markers and differential diagnosis is crucial to avoid misdiagnosis and to improve diagnostic accuracy of this tumor.

Objective:To explore the diagnostic accuracy and application value of 3.0 T non-contrast coronary magnetic resonance angiography (CMRA) in evaluating coronary artery in children with Kawasaki disease (KD).Methods:From May 2019 to January 2022, 75 children diagnosed with KD in our hospital were enrolled. All the patients underwent CMRA and transthoracic echocardiography (TTE) in one week, twenty-six of whom underwent coronary CT angiography (CCTA) or invasive coronary angiography (ICA) within two weeks. The diagnostic performance of CMRA and TTE was evaluated with CCTA/ICA as reference standard by per-patient basis, per-vessel basis, per-segment basis. Sensitivity and specificity of CMRA and TTE was compared by paired chi square test.The distribution of coronary artery aneurysm (CAA), thrombosis and other pathological changes of coronary artery were recorded and compared between two methods. The patients′ height and weight were collected to calculate the Z value. Z value>2.5 was defined as CAA.Results:All patients successfully completed CMRA examinations. Among the 26 patients, the sensitivity of CMRA was significantly higher than that of TTE by per coronary artery[97.7%(43/44)vs.84.1%(37/44), χ2=4.17, P<0.05]. CMRA showed a higher sensitivity than that of TTE both by proximal segments and middle/distal segments [97.7%(43/44)vs. 84.1%(37/44), 100%(21/21) vs. 52.4%(11/21), χ2=10.08, 7.11, both P<0.05). A total of 115 CAAs was found by CMRA, while only 87 (75.7%) CAAs were observed by TTE. Of the 28 (24.3%) CAAs missed by TTE, 16 (57.1%) were located in right coronary artery (RCA), 2(7.1%) in left main coronary artery, 7(25.0%) in left anterior ascending coronary artery (LAD) and 3(10.7%) in left circumflex coronary artery (LCX). Eleven (39.3%) missed CAAs by TTE were located in the proximal segment of RCA, LMCA, LAD and LCX, and 17 (60.7%) missed CAAs were located in the middle and distal segments. TTE missed coronary thrombosis in 5 patients compared with CMRA. Conclusions:3.0 T non-contrast CMRA is non-invasive and non-radiation, and the image quality can meet the needs of diagnosis, especially for detection of CAAs in RCA or in middle and distal segments of coronary artery in KD patients.