A Systematic Review and Meta-Analysis of Mapping Biopsy for Primary Extramammary Paget's Disease in Reducing Recurrence Following Surgical Excision.

Objective: To examine the association between the performance of mapping biopsies and surgical outcomes postexcision of extramammary Paget's disease (EMPD). Background: Primary EMPD is a rare entity associated with poorly defined surgical margins and difficult-to-access sites of lesions. Surgical resection with clear margins remains the preferred management method. The use of mapping biopsies might be beneficial, particularly in lowering disease recurrence. Methods: Available literature was reviewed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses methodology before a fixed-effect meta-analysis was performed to identify the presence of a correlation between performing mapping biopsies and positive margins on permanent sections as well as disease-free survival. Additional study results not included in the quantitative assessment were qualitatively assessed and reported. Results: A total of 12 studies were shortlisted for final analysis. 294 patients who underwent mapping biopsies and 48 patients who did not undergo mapping biopsies were included in the assessment. Forest plot analysis revealed a pooled rate ratio of 0.50 (95% CI, 0.32-0.77) in the prevalence of positive margins in patients with mapping biopsies performed as compared to patients without. The pooled rate ratio of the prevalence of disease-free survival in patients with mapping biopsies performed as compared to patients without was 1.38 (95% CI, 1.03-1.84). Qualitative assessment of the remaining selected studies revealed equivocal results. Conclusions: Mapping biopsies are able to improve EMPD surgical excision outcomes but given the rarity of the disease and heterogeneity of mapping biopsy procedures, further confirmation with randomized controlled trials or a larger patient pool is necessary.

Clinicopathological and treatment response characteristics of updated rhabdomyosarcoma histomolecular subtypes: An Asian population-based study.

AIM: New histomolecular subtypes of rhabdomyosarcoma have recently been defined but their corresponding clinical characteristics are not well described. Also, these clinical phenotypes vary greatly by age and ethnicity but have not been profiled in Asian populations. Thus, we sought to determine the landscape of rhabdomyosarcoma subtypes in a national Asian cohort and compare clinical characteristics among age groups and molecular subtypes. METHODS: We performed a retrospective population-based study of all rhabdomyosarcoma patients in Singapore public hospitals from 2004 to 2014 (n = 67), and assigned histomolecular subtypes according to the updated 2020 WHO classification of soft tissue tumors following central pathology review and molecular profiling. RESULTS: Age-specific prevalence followed a tri-modal peak. There were significantly more embryonal and alveolar (p = 0.032) and genitourinary (non-bladder/prostate) tumors (p = 0.033) among children. Older age was associated with complete resection among spindle cell/sclerosing tumors (p = 0.027), with the omission of chemotherapy among embryonal tumors (p = 0.001), and with poorer survival among embryonal and alveolar tumors (p = 0.026, p = 0.022, respectively). Overall survival differed with stage, group, and surgical resection, adjusted for age group (p = 0.004, p = 0.001, p = 0.004, respectively). Spindle-cell/sclerosing tumors showed an indolent phenotype with a significantly lower incidence of nodal metastasis (p = 0.002), but two of 15 patients with MYOD1 mutations had a contrastingly aggressive disease. CONCLUSION: Disease and treatment response profiles of rhabdomyosarcoma subtypes vary significantly between adults and children, especially surgical resectability. In our Asian population, poorer outcomes were observed in adults with embryonal and alveolar tumors, while activating mutations influence the behavior of otherwise favorable spindle cell/sclerosing tumors.

18F-FMISO PET-guided dose escalation with multifield optimization intensity-modulated proton therapy in nasopharyngeal carcinoma.

PURPOSE: The purpose of this study was to evaluate the radiotherapy planning feasibility of dose escalation with intensity-modulated proton therapy (IMPT) to hypoxic tumor regions identified on 18F-Fluoromisonidazole (FMISO) positron emission tomography and computed tomography (PET-CT) in NPC. MATERIALS AND METHODS: Nine patients with stages T3-4N0-3M0 NPC underwent 18F-FMISO PET-CT before and during week 3 of radiotherapy. The hypoxic volume (GTVhypo) is automatically generated by applying a subthresholding algorithm within the gross tumor volume (GTV) with a tumor to muscle standardized uptake value (SUV) ratio of 1.3 on the 18F-FMISO PET-CT scan. Two proton plans were generated for each patient, a standard plan to 70 Gy and dose escalation plan with upfront boost followed by standard 70GyE plan. The stereotactic boost was planned with single-field uniform dose optimization using two fields to deliver 10 GyE in two fractions to GTVhypo. The standard plan was generated with IMPT with robust optimization to deliver 70GyE, 60GyE in 33 fractions using simultaneous integrated boost technique. A plan sum was generated for assessment. RESULTS: Eight of nine patients showed tumor hypoxia on the baseline 18F-FMISO PET-CT scan. The mean hypoxic tumor volume was 3.9 cm3 (range .9-11.9cm3 ). The average SUVmax of the hypoxic volume was 2.2 (range 1.44-2.98). All the dose-volume parameters met the planning objectives for target coverage. Dose escalation was not feasible in three of eight patients as the D0.03cc of temporal lobe was greater than 75GyE. CONCLUSIONS: The utility of boost to the hypoxic volume before standard course of radiotherapy with IMPT is dosimetrically feasible in selected patients. Clinical trials are warranted to determine the clinical outcomes of this approach.

The Challenge of "Monomorphic" Mucoepidermoid Carcinoma-Report of a Rare Case with Pure Spindle-Clear Cell Morphology.

BACKGROUND: Mucoepidermoid carcinoma is a malignant salivary gland tumor which, in most cases, is composed of variable proportions of mucous, epidermoid, and intermediate cells. METHODS: We report a case of parapharyngeal mucoepidermoid carcinoma with highly unusual ("monomorphic") light microscopic features as well as atypical immunohistochemical properties. Molecular analysis was performed using the TruSight RNA fusion panel. RESULTS: The tumor featured heretofore undescribed histopathological features: sheets and nests composed of monomorphic neoplastic (plump spindle to epithelioid) cells with no mucous, intermediate, glandular/columnar, or any other cell type identified. The neoplastic cells displayed variable clear cell change and only expressed cytokeratin 7. Despite this non-classical morphology, the presence of the classical CRTC1::MAML2 fusion was demonstrated. CONCLUSIONS: Mucoepidermoid carcinoma featuring a uniform ("monomorphic") population of neoplastic cells is a novel observation. A confident diagnosis of mucoepidermoid carcinoma can be made upon detection of the CRTC1/3::MAML2 fusion. Our case increases the spectrum of histopathological appearances that mucoepidermoid carcinoma may display.

Artificial intelligence defines protein-based classification of thyroid nodules.

Determination of malignancy in thyroid nodules remains a major diagnostic challenge. Here we report the feasibility and clinical utility of developing an AI-defined protein-based biomarker panel for diagnostic classification of thyroid nodules: based initially on formalin-fixed paraffin-embedded (FFPE), and further refined for fine-needle aspiration (FNA) tissue specimens of minute amounts which pose technical challenges for other methods. We first developed a neural network model of 19 protein biomarkers based on the proteomes of 1724 FFPE thyroid tissue samples from a retrospective cohort. This classifier achieved over 91% accuracy in the discovery set for classifying malignant thyroid nodules. The classifier was externally validated by blinded analyses in a retrospective cohort of 288 nodules (89% accuracy; FFPE) and a prospective cohort of 294 FNA biopsies (85% accuracy) from twelve independent clinical centers. This study shows that integrating high-throughput proteomics and AI technology in multi-center retrospective and prospective clinical cohorts facilitates precise disease diagnosis which is otherwise difficult to achieve by other methods.

Topical Biological Agents as Adjuncts to Improve Wound Healing in Chronic Diabetic Wounds: A Systematic Review of Clinical Evidence and Future Directions.

Diabetes is a leading chronic illness in the modern world and 19-34% develop chronic diabetic foot ulcers (DFUs) in their lifetime, often necessitating amputation. The reduction in tissue growth factors and resulting imbalance between proteolytic enzymes and their inhibitors, along with systemic factors impairing healing appear particularly important in chronic wounds. Growth factors applied topically have thus been suggested to be a non-invasive, safe, and cost-effective adjunct to improve wound healing and prevent complications. Comprehensive database searches of MEDLINE via PubMed, EMBASE, Cochrane, and ClinicalTrials.gov were performed to identify clinical evidence and ongoing trials. The risk of bias analysis included randomized controlled trials (RCTs) was performed using the Cochrane Risk of Bias 2.0 tool. We included randomized controlled trials that compared the use of a topical biologic growth factor-containing regimen to any other regimen. Primary outcomes of interest were time to wound closure, healing rate, and time. Secondary outcomes included the incidence of adverse events such as infection. A total of 41 trials from 1992-2020 were included in this review, with a total recorded 3,112 patients. Platelet-derived growth factors (PDGF) in the form of becaplermin gel are likely to reduce the time of closure, increase the incidence of wound closure, and complete wound healing. Human umbilical cord-related treatments, dehydrated human amnion and chorion allograft (dHACA), and hypothermically stored amniotic membrane (HSAM), consistently increased the rates and incidence of complete ulcer healing while reducing ulcer size and time to complete ulcer healing. Fibroblast growth factor-1 (FGF1) showed only a slight benefit in multiple studies regarding increasing complete ulcer healing rates and incidence while reducing ulcer size and time to complete ulcer healing, with a few studies showing no statistical difference from placebo. Platelet-rich fibrin (PRF) is consistent in reducing the time to complete ulcer healing and increasing wound healing rate but may not reduce ulcer size or increase the incidence of complete ulcer healing. Targeting the wound healing pathway via the extrinsic administration of growth factors is a promising option to augment wound healing in diabetic patients. Growth factors have also shown promise in specific subgroups of patients who are at risk of significantly impaired wound healing such as those with a history of secondary infection and vasculopathy. As diabetes impairs multiple stages of wound healing, combining growth factors in diabetic wound care may prove to be an area of interest. Evidence from this systematic literature review suggests that topical adjuncts probably reduce time to wound closure, reduce healing time, and increase the healing rate in patients with chronic DFUs.

Breast-related extranodal Rosai-Dorfman disease presenting as subcutaneous masses with thick hyperechoic rim, with review of the literature.

Rosai-Dorfman disease (RDD) is a rare, idiopathic histiocytic proliferative disorder. We report two cases of RDD related to the breast which showed common distinctive imaging characteristics which can help facilitate accurate diagnosis and appropriate management.

Deep Learning-Guided Fiberoptic Raman Spectroscopy Enables Real-Time In Vivo Diagnosis and Assessment of Nasopharyngeal Carcinoma and Post-treatment Efficacy during Endoscopy.

In this work, we develop a deep learning-guided fiberoptic Raman diagnostic platform to assess its ability of real-time in vivo nasopharyngeal carcinoma (NPC) diagnosis and post-treatment follow-up of NPC patients. The robust Raman diagnostic platform is established using innovative multi-layer Raman-specified convolutional neural networks (RS-CNN) together with simultaneous fingerprint and high-wavenumber spectra acquired within sub-seconds using a fiberoptic Raman endoscopy system. We have acquired a total of 15,354 FP/HW in vivo Raman spectra (control: 1761; NPC: 4147; and post-treatment (PT): 9446) from 888 tissue sites of 418 subjects (healthy control: 85; NPC: 82; and PT: 251) during endoscopic examination. The optimized RS-CNN model provides an overall diagnostic accuracy of 82.09% (sensitivity of 92.18% and specificity of 73.99%) for identifying NPC from control and post-treatment patients, which is superior to the best diagnosis performance (accuracy of 73.57%; sensitivity of 89.74%; and specificity of 58.10%) using partial-least-squares linear-discriminate-analysis, proving the robustness and high spectral information sensitiveness of the RS-CNN model developed. We further investigate the saliency map of the best RS-CNN models using the correctly predicted Raman spectra. The specific Raman signatures that are related to the cancer-associated biomolecular variations (e.g., collagens, lipids, and nucleic acids) are uncovered in the map, validating the diagnostic capability of RS-CNN models to correlate with biomolecular signatures. Deep learning-based Raman spectroscopy is a powerful diagnostic tool for rapid screening and surveillance of NPC patients and can also be deployed for longitudinal follow-up monitoring of post-treatment NPC patients to detect early cancer recurrences in the head and neck.

Bizarre giant cells in human angiosarcoma exhibit chemoresistance and contribute to poor survival outcomes.

Giant cells (GC) are a poorly understood subset of tumor cells that have been increasingly recognized as a potential contributor to tumor heterogeneity and treatment resistance. We aimed to characterize the biological and clinical significance of GC in angiosarcoma, an aggressive rare cancer of endothelial origin. Archival angiosarcoma samples were examined for the presence of GC and compared with clinicopathological as well as NanoString gene expression data. GC were examined in angiosarcoma cell lines MOLAS and ISOHAS using conventional and electron microscopy, single cell whole genome profiling, and other assays. In the cell lines, GC represented a rare population of mitotically active, non-senescent CD31+ cells, and shared similar genomic profiles with regular-sized cells, consistent with a malignant endothelial phenotype. GC remained viable and persisted in culture following exposure to paclitaxel and doxorubicin. In patient samples, GC were present in 24 of 58 (41.4%) cases. GC was correlated with poorer responses to chemotherapy (25.0% vs 73.3%, P = 0.0213) and independently contributed to worse overall survival outcomes (hazard ratio 2.20, 95% confidence interval 1.17-4.15, P = 0.0142). NanoString profiling revealed overexpression of genes, including COL11A1, STC1, and ERO1A, accompanied by upregulation of immune-related metabolic stress and metastasis/matrix remodeling pathways in GC-containing tumors. In conclusion, GC may contribute to chemoresistance and poor prognosis in angiosarcoma.

Surgical Excision of Thoracic Osteoblastoma with Secondary Aneurysmal Bone Cyst from a 12-Year-Old Child.

INTRODUCTION: Osteoblastoma is a primary benign tumour which commonly presents in the younger population during the second decade of life. However, more aggressive osteoblastomas may present with features of aneurysmal bone cyst, and these can occur at uncommon locations. CASE PRESENTATION: We report the case of a 12-year-old child having an osteoblastoma on the left side of T11 with secondary aneurysmal bone cyst presenting with neurological deficits and myelopathic symptoms. Surgical debulking of the lesion with decompression laminectomy and posterior instrumentation of the spine was performed. The child is currently recovering well with improvement of neurological deficits. DISCUSSION/CONCLUSION: Osteoblastoma with aneurysmal bone cyst of the thoracic spine is a rare condition with few reports in the literature, and surgical intervention with complete excision has been demonstrated here with recovery of neurological function.

Multiomic analysis and immunoprofiling reveal distinct subtypes of human angiosarcoma.

Angiosarcomas are rare, clinically aggressive tumors with limited treatment options and a dismal prognosis. We analyzed angiosarcomas from 68 patients, integrating information from multiomic sequencing, NanoString immuno-oncology profiling, and multiplex immunohistochemistry and immunofluorescence for tumor-infiltrating immune cells. Through whole-genome sequencing (n = 18), 50% of the cutaneous head and neck angiosarcomas exhibited higher tumor mutation burden (TMB) and UV mutational signatures; others were mutationally quiet and non-UV driven. NanoString profiling revealed 3 distinct patient clusters represented by lack (clusters 1 and 2) or enrichment (cluster 3) of immune-related signaling and immune cells. Neutrophils (CD15+), macrophages (CD68+), cytotoxic T cells (CD8+), Tregs (FOXP3+), and PD-L1+ cells were enriched in cluster 3 relative to clusters 2 and 1. Likewise, tumor inflammation signature (TIS) scores were highest in cluster 3 (7.54 vs. 6.71 vs. 5.75, respectively; P < 0.0001). Head and neck angiosarcomas were predominant in clusters 1 and 3, providing the rationale for checkpoint immunotherapy, especially in the latter subgroup with both high TMB and TIS scores. Cluster 2 was enriched for secondary angiosarcomas and exhibited higher expression of DNMT1, BRD3/4, MYC, HRAS, and PDGFRB, in keeping with the upregulation of epigenetic and oncogenic signaling pathways amenable to targeted therapies. Molecular and immunological dissection of angiosarcomas may provide insights into opportunities for precision medicine.

Phenotype Classification using Proteome Data in a Data-Independent Acquisition Tensor Format.

A novel approach for phenotype prediction is developed for data-independent acquisition (DIA) mass spectrometric (MS) data without the need for peptide precursor identification using existing DIA software tools. The first step converts the DIA-MS data file into a new file format called DIA tensor (DIAT), which can be used for the convenient visualization of all the ions from peptide precursors and fragments. DIAT files can be fed directly into a deep neural network to predict phenotypes such as appearances of cats, dogs, and microscopic images. As a proof of principle, we applied this approach to 102 hepatocellular carcinoma samples and achieved an accuracy of 96.8% in distinguishing malignant from benign samples. We further applied a refined model to classify thyroid nodules. Deep learning based on 492 training samples achieved an accuracy of 91.7% in an independent cohort of 216 test samples. This approach surpassed the deep-learning model based on peptide and protein matrices generated by OpenSWATH. In summary, we present a new strategy for DIA data analysis based on a novel data format called DIAT, which enables facile two-dimensional visualization of DIA proteomics data. DIAT files can be directly used for deep learning for biological and clinical phenotype classification. Future research will interpret the deep-learning models emerged from DIAT analysis.

DPHL: A DIA Pan-human Protein Mass Spectrometry Library for Robust Biomarker Discovery.

To address the increasing need for detecting and validating protein biomarkers in clinical specimens, mass spectrometry (MS)-based targeted proteomic techniques, including the selected reaction monitoring (SRM), parallel reaction monitoring (PRM), and massively parallel data-independent acquisition (DIA), have been developed. For optimal performance, they require the fragment ion spectra of targeted peptides as prior knowledge. In this report, we describe a MS pipeline and spectral resource to support targeted proteomics studies for human tissue samples. To build the spectral resource, we integrated common open-source MS computational tools to assemble a freely accessible computational workflow based on Docker. We then applied the workflow to generate DPHL, a comprehensive DIA pan-human library, from 1096 data-dependent acquisition (DDA) MS raw files for 16 types of cancer samples. This extensive spectral resource was then applied to a proteomic study of 17 prostate cancer (PCa) patients. Thereafter, PRM validation was applied to a larger study of 57 PCa patients and the differential expression of three proteins in prostate tumor was validated. As a second application, the DPHL spectral resource was applied to a study consisting of plasma samples from 19 diffuse large B cell lymphoma (DLBCL) patients and 18 healthy control subjects. Differentially expressed proteins between DLBCL patients and healthy control subjects were detected by DIA-MS and confirmed by PRM. These data demonstrate that the DPHL supports DIA and PRM MS pipelines for robust protein biomarker discovery. DPHL is freely accessible at https://www.iprox.org/page/project.html?id=IPX0001400000.

Clinicopathologic Features and Whole Genome Sequencing of a Primary Osteosarcoma of the Uterus.

Primary osteosarcoma (OS) of the uterus is a distinctly rare and aggressive disease with fewer than 20 cases reported worldwide. We describe a case of primary uterine OS with rapid development of pulmonary and brain metastasis in a 50-year-old woman. Histopathologic examination of the uterine tumor showed atypical spindle cells producing an osteoid matrix with calcification in keeping with OS. Despite initial response to doxorubicin and ifosfamide, the patient succumbed to brain metastases just 8 months from diagnosis. Whole genome sequencing was performed on tumor and blood samples to analyze genetic alterations in this highly aggressive tumor. A pathogenic somatic missense mutation resulting in substitution of glutamate for lysine at position 653 within the protein kinase domain of the platelet-derived growth factor receptor beta (PDGFRB) was found. The PDGF pathway is involved in cell proliferation and angiogenesis, and it has been implicated in malignancy. Crucially, this pathogenic mutation may be amenable to PDGFR tyrosine kinase inhibition, representing a possible treatment approach in this rare sarcoma.

Genomic profile of breast sarcomas: a comparison with malignant phyllodes tumours.

PURPOSE: We aimed to investigate the genomic profile of breast sarcomas (BS) and compare with that of malignant phyllodes tumours (MPT). METHODS: DNA was extracted from formalin-fixed, paraffin-embedded (FFPE) specimens from 17 cases of BS diagnosed at Singapore General Hospital from January 1991 to December 2014. Targeted deep sequencing and copy number variation (CNV) analysis on 16 genes, which included recurrently mutated genes in phyllodes tumours and genes associated with breast cancer, were performed on these samples. Genetic alterations (GA) observed were summarised and analysed. RESULTS: Nine cases met the quality control requirements for both targeted deep sequencing and CNV analysis. Three (33.33%) were angiosarcomas and 6 (66.67%) were non-angiosarcomas. In the non-angiosarcoma group, 83.33% (n = 5) of the patients had GA in the TERT gene. The other commonly mutated genes in this group of tumours were MED12 (n = 4, 66.67%), BCOR (n = 4, 66.67%), KMT2D (n = 3, 50%), FLNA (n = 3, 50%) and NF1 (n = 3, 50%). In contrast, none of the angiosarcomas had mutations or copy number alterations in TERT, MED12, BCOR, FLNA or NF1. Eighty percent of patients with GA in TERT (n = 5) had concurrent mutations in MED12. Sixty percent (n = 3) of these cases also demonstrated GA in NF1, PIK3CA or EGFR which are known cancer driver genes. CONCLUSIONS: The non-angiosarcoma group of BS was found to share similar GA as those described for MPT, which may suggest a common origin and support their consideration as a similar group of tumours with regard to management and prognostication.

Biological significance and prognostic relevance of peripheral blood neutrophil-to-lymphocyte ratio in soft tissue sarcoma.

Peripheral blood indices of systemic inflammation such as the neutrophil-lymphocyte ratio (NLR) have been shown to be prognostic in various cancers. We aim to investigate the clinical significance of these indices in patients with soft tissue sarcoma (STS). Seven hundred and twelve patients with available blood counts at diagnosis and/or metastatic relapse were retrospectively examined. An optimal cutoff for NLR-high (>2.5) in predicting overall survival (OS) was determined using receiver operating curve analyses. Survival analyses were performed using the Kaplan-Meier method and multivariate Cox proportional models. Our results show that NLR was significantly higher in patients with distant metastasis at diagnosis (n = 183) compared to those without (n = 529) (median: 4.36 vs 2.85, p < 0.0001). Progression of localized disease at diagnosis to metastatic relapse within the same patients was associated with an interval increase in NLR (median: 3.21 vs 3.74, p = 0.0003). In multivariate analysis, NLR-high was the only consistent factor independently associated with both worse OS (HR 1.53, 95% CI 1.10-2.13, p = 0.0112) and relapse-free survival (HR 1.41, 95% CI 1.08-1.85, p = 0.0125) in localized disease, as well as OS (HR 1.82, 95% CI 1.16-2.85, p = 0.0087) in metastatic/unresectable disease. In conclusion, high NLR is an independent marker of poor prognosis among patients with STS.

The Approach to Solitary Fibrous Tumors: Are Clinicopathological Features and Nomograms Accurate in the Prediction of Prognosis?

INTRODUCTION: Currently, factors such as size, mitotic rate, and degree of necrosis have been shown to influence survival in patients with solitary fibrous tumors (SFTs); however, there remains no consensus regarding the associations between tumor characteristics and the malignant nature of these tumors. The aim of this article was to identify factors that would help in prognosticating SFTs and to validate the MD Anderson Cancer Center (MDACC) SFT nomogram in the largest known series of SFTs treated in an Asian population. METHODS: A retrospective review of all patients with a diagnosis of SFT treated surgically in our institution between 2005 and 2015 was carried out. Basic demographics, clinicopathological, and surgical factors were analyzed for association with clinical outcomes. Factors that predicted for distant recurrence (DR) and poor survival were identified as high-risk features. The MDACC nomogram was validated by assessing the extent of discrimination, quantified using Harrell's concordance index (C-index). RESULTS: Fifty-nine patients were included in analysis. Significant univariate associations for DR were found for mitotic rate ( P = .05) and presence of necrosis ( P = .04). Significant univariate associations for overall survival were found for presence of recurrence ( P = .035), presence of necrosis ( P = .072), and mitotic rate ( P = .033). The C-index associated with the nomogram was 0.75. CONCLUSION: There is a negative association for DR and overall survival, with the mitotic rate and presence of necrosis. We propose that SFTs with these features should be regarded as high risk. The MDACC nomogram generally predicts well for patients in an Asian population.

TFE3-Expressing Epithelioid Rich Perivascular Epithelioid Cell Neoplasm (PEComa) of the Bladder with Unusual Benign Course.

Perivascular epithelioid cell tumor (PEComa) is an uncommon tumor which presents with epithelioid and spindled cell morphology and is immunoreactive for myogenic and melanocytic markers. Recently, a subset of PEComas has been reported to harbor TFE3 gene rearrangement.In this case report, we describe a TFE3-expressing primary bladder PEComa in a 27-year-old male patient with acute myeloid leukaemia in remission. The tumor displayed epithelioid morphology with surrounding delicate blood vessels and was devoid of a prominent spindle cell component. Malignant features were not identified. The tumor expressed HMB45, CD117, and focal patchy positive expression for SMA. TFE3 gene translocation was confirmed by Fluorescence in-situ hybridization. RT-PCR assay confirmed the presence of SFPQ-TFE3 gene fusion.In contrast to previously reported aggressive TFE3 gene-rearranged bladder PEComa cases, our case shows benign histologic and clinical features. Current clinical follow-up also shows a benign course.