Discriminative ensemble meta-learning with co-regularization for rare fundus diseases diagnosis.

Deep neural networks (DNNs) have been widely applied in the medical image community, contributing to automatic ophthalmic screening systems for some common diseases. However, the incidence of fundus diseases patterns exhibits a typical long-tailed distribution. In clinic, a small number of common fundus diseases have sufficient observed cases for large-scale analysis while most of the fundus diseases are infrequent. For these rare diseases with extremely low-data regimes, it is challenging to train DNNs to realize automatic diagnosis. In this work, we develop an automatic diagnosis system for rare fundus diseases, based on the meta-learning framework. The system incorporates a co-regularization loss and the ensemble-learning strategy into the meta-learning framework, fully leveraging the advantage of multi-scale hierarchical feature embedding. We initially conduct comparative experiments on our newly-constructed lightweight multi-disease fundus images dataset for the few-shot recognition task (namely, FundusData-FS). Moreover, we verify the cross-domain transferability from miniImageNet to FundusData-FS, and further confirm our method's good repeatability. Rigorous experiments demonstrate that our method can detect rare fundus diseases, and is superior to the state-of-the-art methods. These investigations demonstrate that the potential of our method for the real clinical practice is promising.

Synthetic CT Assessment of Lesions in Children With Rare Musculoskeletal Diseases.

Imaging modalities such as computed tomography (CT) are critical for monitoring musculoskeletal abnormalities in children with rare diseases. However, CT exposes patients to radiation, which limits its utility in the clinical setting, particularly during longitudinal evaluation. Synthetic CT is a novel, noncontrast, and rapid MRI method that can provide CT-like images without any radiation exposure and is easily performed in conjunction with traditional MRI, which detects soft-tissue and bone marrow abnormalities. To date, an evaluation of synthetic CT in pediatric patients with rare musculoskeletal diseases has been lacking. In this case series, the capability of synthetic CT to identify musculoskeletal lesions accurately in 2 rare disease patients is revealed. In Case 1, synthetic CT, in agreement with routine CT, identified an intraosseous lesion in the right femoral neck in a 16-year-old female with fibrous dysplasia, whereas standard-of-care MRIs additionally revealed mild surrounding edema-like bone marrow signal. For Case 2, synthetic CT applied to a 12-year-old female with fibrodysplasia ossificans progressiva revealed heterotopic ossification present along the cervical spine that had caused the fusion of multiple vertebrae. Our evaluation of synthetic CT offers important insights into the feasibility and utility of this methodology in children with rare diseases affecting the musculoskeletal system.

Rare embryonal and sarcomatous central nervous system tumours: State-of-the art and future directions.

The introduction of molecular methods into the diagnostics of central nervous system (CNS) tumours and the subsequent deciphering of their molecular heterogeneity has resulted in a significant impact on paediatric neurooncology. Particularly in the field of rare embryonal and sarcomatous CNS tumours, novel tumour types have been delineated and introduced in the recent 5th edition of the WHO classification of CNS tumours. The rarity and novelty of these tumour types result in diagnostic and therapeutic challenges. Apart from distinct histopathological and molecular features, these tumour types exhibit characteristic clinical properties and require different therapeutic approaches for optimal patient management. However, based on the limited availability of clinical data, current therapeutic recommendations have to be based on data from small, predominantly retrospective patient cohorts. Within this article, we provide guidance for diagnostic work-up and clinical management of rare CNS embryonal tumours ('embryonal tumour with multi-layered rosettes', ETMR; 'CNS neuroblastoma, FOXR2-activated', CNS NB-FOXR2; 'CNS tumour with BCOR-ITD, CNS BCOR-ITD) and rare CNS sarcomatous tumours ('primary intracranial sarcoma, DICER1-mutant', CNS DICER1; 'CIC-rearranged sarcoma', CNS CIC). By emphasizing the significant consequences on patient management in paediatric CNS tumours, we want to encourage wide implementation of comprehensive molecular diagnostics and stress the importance for joint international efforts to further collect and study these rare tumour types.

Brenner tumors.

Brenner tumors are rare ovarian neoplasms composed of ovarian transition cells surrounded by dense fibrous tissue. Most of them are small tumors (<2 cm), detected incidentally in asymptomatic women. Its predominantly fibrous content results in relatively low signal on T2 weighted images, establishing differential diagnosis with ovarian fibroma and thecoma. Their imaging features are very similar, the differentiation is based on secondary characteristics, such as signs or symptoms of estrogen excess and the presence of a second ovarian neoplasm, which has been reported in up to 30% of patients with Brenner tumor. Although originally thought to be universally benign, there have been scattered reports in the past decades of borderline and malignant forms of Brenner tumors.

Role of radiotherapy in the treatment of primary vaginal cancer: Recommendations of the French society for radiation oncology.

Primary vaginal cancers are rare tumours, for which external beam radiotherapy and brachytherapy are major treatment tools. Given the complexity of brachytherapy techniques, the treatment should be performed in specialised centres. We present the recommendations of the French society for radiation oncology on the indications and techniques for external beam radiotherapy and brachytherapy for primary vaginal cancer.

Role of radiotherapy in the management of vulvar cancer: Recommendations of the French society for radiation oncology.

Primary vulvar carcinomas are rare gynaecological cancers, for which surgery is the mainstay of treatment. There is however a major place for external beam radiotherapy in the situation of inoperable locally advanced tumours and/or as adjuvant therapy, when there are risk factors for locoregional relapse. We present the recommendations of the French society for radiation oncology on the indications and techniques for radiotherapy in the treatment of primary vulvar cancer.

Artificial Intelligence in Medical Imaging and its Impact on the Rare Disease Community: Threats, Challenges and Opportunities.

Almost 1 in 10 individuals can suffer from one of many rare diseases (RDs). The average time to diagnosis for an RD patient is as high as 7 years. Artificial intelligence (AI)-based positron emission tomography (PET), if implemented appropriately, has tremendous potential to advance the diagnosis of RDs. Patient advocacy groups must be active stakeholders in the AI ecosystem if we are to avoid potential issues related to the implementation of AI into health care. AI medical devices must not only be RD-aware at each stage of their conceptualization and life cycle but also should be trained on diverse and augmented datasets representative of the end-user population including RDs. Inability to do so leads to potential harm and unsustainable deployment of AI-based medical devices (AIMDs) into clinical practice.

A case of congenital partial absence of the left pericardium presenting with atypical chest pain.

Congenital absence of the pericardium (CAP) is a rare cardiac malformation and can be defined as the partial or total absence of the fibroelastic sac that surrounds the heart and great vessels. As the patients are often asymptomatic or have nonspecific symptoms, the diagnosis of this rare congenital anomaly is difficult. Therefore, it is usually diagnosed incidentally during imaging, intraoperatively, or during postmortem examinations. In this regard, it is important to keep specific images in mind during the examination and to suspect CAP to make an accurate diagnosis. In this report, we present a case of a 42-year-old male who presented with a complaint of atypical chest pain and was diagnosed with CAP using multimodality imaging.

Rare double orifice mitral valve malformation associated with bicuspid aortic valve in Turner syndrome: diagnosed by a series of novel three-dimensional echocardiography and literature review.

BACKGROUND: Patients with both double orifice mitral valve (DOMV) and bicuspid aortic valve (BAV) malformation are rare. Although DOMV or BAV can be detected in some genetic syndromes, it has not been reported to simultaneously appear in Turner syndrome (TS). TrueVue, TouchVue, and TrueVue Glass are the latest technologies in advanced three-dimensional echocardiography (3DE), which is an important information supplement to two-dimensional echocardiography (2DE) for the diagnosis of congenital cardiac malformations. Herein we report the novel use of the above-mentioned technologies in the diagnosis and evaluation of a rare, combined valve malformation. Meanwhile, we also reviewed the literature for cases involving both DOMV and BAV and their association with various genetic syndromes. CASE PRESENTATION: We present the case of a 5-year-old girl diagnosed with TS because of a developmental delay. DOMV and BAV were found through echocardiographic examination. Three-dimensional transthoracic echocardiography as well as a series of novel advanced techniques were applied to clearly display the spatial structure of all tiers of the mitral valve apparatus, aortic valve, and arch to facilitate an accurate diagnosis. CONCLUSIONS: This is the first case in which both DOMV and BAV were associated with TS. Innovative TrueVue and TrueVue Glass offer unprecedented photographic stereoscopic images, while TouchVue technology greatly improved the ultrasonic diagnostic workflow and the diagnostic performance of rare valve malformations by adding virtual light sources to display realistic light-shadow effects.

Central papillary adenoma of the lung diagnosed in a bronchoscopy-guided FNA: Cytological and histological characterization of this rare entity.

Pulmonary papillary adenoma (PA) is an unusual tumor with only 32 reported cases to date. We present a case of a 69-year-old man, a smoker from the age of 12, with a central mass in the pulmonary left lower lobe identified in a PET-CT scan. Microscopical analysis of the Fine Needle Aspiration (FNA) samples showed fragments of a tumor comprised of abundant papillary structures lined by a monolayer of cytologically bland columnar to cuboidal epithelial cells. The immunohistochemical stains were positive for CK7, TTF-1 and EMA in the epithelial cells, and negative for MYC. Based on the imaging tests, histological features and immunohistochemical profile, the tumor was diagnosed as pulmonary PA. The cytologic and histologic features of this rare entity are described in detail and the value of FNA as an essential presurgical diagnostic procedure is emphasized.

Key Imaging Findings for the Prospective Diagnosis of Rare Diseases of the Gallbladder and Cystic Duct.

There are various diseases of the gallbladder and cystic duct, and imaging diagnosis is challenging for the rare among them. However, some rare diseases show characteristic imaging findings or patient history; therefore, familiarity with the imaging presentation of rare diseases may improve diagnostic accuracy and patient management. The purpose of this article is to describe the imaging findings of rare diseases of the gallbladder and cystic duct and identify their pathological correlations with these diseases.

Fundamental mechanistic insights from rare but paradigmatic neuroimmunological diseases.

The pathophysiology of complex neuroimmunological diseases, such as multiple sclerosis and autoimmune encephalitis, remains puzzling - various mechanisms that are difficult to dissect seem to contribute, hampering the understanding of the processes involved. Some rare neuroimmunological diseases are easier to study because their presentation and pathogenesis are more homogeneous. The investigation of these diseases can provide fundamental insights into neuroimmunological pathomechanisms that can in turn be applied to more complex diseases. In this Review, we summarize key mechanistic insights into three such rare but paradigmatic neuroimmunological diseases - Susac syndrome, Rasmussen encephalitis and narcolepsy type 1 - and consider the implications of these insights for the study of other neuroimmunological diseases. In these diseases, the combination of findings in humans, different modalities of investigation and animal models has enabled the triangulation of evidence to validate and consolidate the pathomechanistic features and to develop diagnostic and therapeutic strategies; this approach has provided insights that are directly relevant to other neuroimmunological diseases and applicable in other contexts. We also outline how next-generation technologies and refined animal models can further improve our understanding of pathomechanisms, including cell-specific and antigen-specific CNS immune responses, thereby paving the way for the development of targeted therapeutic approaches.

[Acute localized dissection of the descending thoracic aorta: A diagnostic trap]. / La dissection aiguë localisée de l'aorte thoracique descendante : un piège diagnostique.

Localized dissection of the descending thoracic aorta; class 3 of the classification proposed by the European Society of Cardiology; is a short and limited length dissection involving the descending thoracic aorta. It is a rare and unrecognized variant that poses a clinical and radiological diagnostic challenge. Indeed, it is manifested by an aspecific clinical profile represented by the acute aortic syndrome and characterized by a confused radiological aspect that entangled with the other differential diagnoses. We would like to emphasize the rarity of this uncommon pathology and the difficulty encountered in defining it based on a case treated in our department and a review of the literature.

Added value of contrast-enhanced ultrasound (CEUS) in the diagnosis of primary retroperitoneal serous adenocarcinoma: a case report.

BACKGROUND: Primary retroperitoneal serous adenocarcinoma (PRSA) is a rare malignant disease. Given the rarity of the disease, the imaging features of PRSA are unclear. Contrast-enhanced ultrasound (CEUS) also plays an important role in the evaluation of the differential diagnosis of retroperitoneal lesions. CASE PRESENTATION: We report the case of a 62-year-old woman of with increased CA125 levels for 1 year who was referred to our hospital. After conducting contrast-enhanced computed tomography and magnetic resonance imaging, the mass was misdiagnosed as a chocolate cyst. After transvaginal ultrasound (TUS) combined with CEUS, cystadenocarcinoma was considered as the initial diagnosis. Pathology results confirmed PRSA as the final diagnosis. CONCLUSIONS: CEUS features of PRSA are reported for the first time based on this case, potentially aiding in the differential diagnosis of this rare entity before surgery.

Radiomics analysis for predicting pembrolizumab response in patients with advanced rare cancers.

BACKGROUND: We present a radiomics-based model for predicting response to pembrolizumab in patients with advanced rare cancers. METHODS: The study included 57 patients with advanced rare cancers who were enrolled in our phase II clinical trial of pembrolizumab. Tumor response was evaluated using Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 and immune-related RECIST (irRECIST). Patients were categorized as 20 "controlled disease" (stable disease, partial response, or complete response) or 37 progressive disease). We used 3D-slicer to segment target lesions on standard-of-care, pretreatment contrast enhanced CT scans. We extracted 610 features (10 histogram-based features and 600 second-order texture features) from each volume of interest. Least absolute shrinkage and selection operator logistic regression was used to detect the most discriminatory features. Selected features were used to create a classification model, using XGBoost, for the prediction of tumor response to pembrolizumab. Leave-one-out cross-validation was performed to assess model performance. FINDINGS: The 10 most relevant radiomics features were selected; XGBoost-based classification successfully differentiated between controlled disease (complete response, partial response, stable disease) and progressive disease with high accuracy, sensitivity, and specificity in patients assessed by RECIST (94.7%, 97.3%, and 90%, respectively; p<0.001) and in patients assessed by irRECIST (94.7%, 93.9%, and 95.8%, respectively; p<0.001). Additionally, the common features of the RECIST and irRECIST groups also highly predicted pembrolizumab response with accuracy, sensitivity, specificity, and p value of 94.7%, 97%, 90%, p<0.001% and 96%, 96%, 95%, p<0.001, respectively. CONCLUSION: Our radiomics-based signature identified imaging differences that predicted pembrolizumab response in patients with advanced rare cancer. INTERPRETATION: Our radiomics-based signature identified imaging differences that predicted pembrolizumab response in patients with advanced rare cancer.

Hybrid Materials Based on Magnetic Iron Oxides with Benzothiazole Derivatives: A Plausible Potential Spectroscopy Probe.

Rare diseases affect a small part of the population, and the most affected are children. Because of the low availability of patients for testing, the pharmaceutical industry cannot develop drugs for the diagnosis of many of these orphan diseases. In this sense, the use of benzothiazole compounds that are highly selective and can act as spectroscopy probes, especially the compound 2-(4'-aminophenyl)benzothiazole (ABT), has been highlighted. This article reports the design of potential contrast agents based on ABT and iron to develop a new material with an efficient mechanism to raise the relaxation rate, facilitating diagnosis. The ABT/δ-FeOOH hybrid material was prepared by grafting (N-(4'-aminophenyl) benzothiazole-2-bromoacetamide) on the surface of the iron oxyhydroxide particles. FTIR spectra confirmed the material formations of the hybrid material ABT/δ-FeOOH. SEM analysis checked the covering of nanoflakes' surfaces in relation to the morphology of the samples. The theoretical calculations test a better binding mode of compound with iron oxyhydroxide. Theoretical findings show the radical capture mechanism in the stabilization of this new material. In this context, Fe3+ ions are an electron acceptor from the organic phase.

Imaging features and radiologic-pathologic correlations of inflammatory pseudotumor-like follicular dendritic cell sarcoma.

BACKGROUND: Inflammatory pseudotumor-like follicular dendritic cell sarcoma (IPT-like FDCS) is a rare tumor. This study aimed to reveal the radiological characteristics of IPT-like FDCS by radiologic-pathologic correlation. RESULTS: We analyzed two cases of IPT-like FDCS in the liver, nine in the spleen, and two in both the liver and spleen concomitantly. IPT-like FDCS presented as well-defined iso- or hypodense masses on unenhanced computed tomography (CT) images in both the liver and spleen. Hyperintensities on T1-weighted images and hypointensities on T2-weighted images with hypointense rings were characteristic features in splenic cases. "Halo signs" were observed in two out of three liver tumors. Hepatic lesions showed significant enhancement, whereas splenic lesions showed only mild enhancement. Delayed annular enhancement was observed in both liver and spleen cases. On ultrasonographic examination, IPT-like FDCS presented as hypoechoic lesions with enhancement similar to that observed on CT. Hyaline fibrous pseudocapsules, which correlated with the hypointensities on T2-weighted images, were microscopically observed at the tumor edge. IPT-like FDCS was characterized by an abundance of small blood vessels and capillaries. Capillaries were also found in the fibrous capsule of some IPT-like FDCSs, which may explain the delayed annular enhancement. CONCLUSIONS: The manifestations of IPT-like FDCS in the liver and spleen showed differences that warrant them to be approached differently during diagnosis. Characteristic radiological findings of IPT-like FDCS included different enhancement patterns between liver and spleen tumors and rim-like hypointensities on T2-weighted images, as well as annular enhancement on CT and magnetic resonance images. These imaging features correlated with tumor pathology.

Enlarged uterine fibroid forming uterine diverticulum during pregnancy: a case report.

BACKGROUND: Although uterine fibroids are a common gynecologic neoplasm, uterine diverticulum accompanied by a uterine fibroid is unique. In addition, pregnancy complicated with uterine diverticulum is extremely rare. We experienced a case of a uterine fibroid that was associated with a uterine diverticulum that enlarged during pregnancy and puerperium. CASE PRESENTATION: A 25-year-old nulligravida woman had an abnormal uterine cavity surrounded by myomatous mass. After natural conception, the mass and pouch had enlarged during pregnancy. Six months after elective cesarean delivery, she underwent laparotomy because of abdominal pain caused by the myomatous mass and the fluid inside. The tumor was connected to the midline of the posterior wall of the normal uterus. The resected tumor was pathologically diagnosed as leiomyoma and diverticulum. CONCLUSIONS: Pregnancy can stimulate uterine fibroids to form uterine diverticula. Resection of the diverticulum and fibroid is a useful option for symptomatic patients with desired future fertility.

Intramedullary spinal cord metastases: Report of three cases and review of the literature.

Intramedullary spinal cord metastases (ISCM) is a rare, but devastating complication of malignant disease. Prognosis is poor, with an overall median survival (OS) of 4 months from the time of diagnosis. Yet, ISCMs are being increasingly diagnosed, related to advances and increased use of imaging and therapies that prolong survival in patients with cancer. Prompt and accurate diagnosis of ISCM is necessary for effective treatment, and magnetic resonance imaging (MRI) is the preferred imaging technique. The optimal management of these patients is controversial because of the multitude of clinical circumstances and the lack of controlled studies on the efficacy of the different therapeutic approaches. Increased awareness of this rare entity may lead to an earlier diagnosis at a stage when neurological deficits are reversible, and therefore, more effective palliation may be achieved. Therefore, we carried out this retrospective research of 3 observations of ISCM, associated with a detailed review of the literature describing the diagnostic, therapeutic and evolutionary characteristics of this special rare entity.