Explainable synthetic image generation to improve risk assessment of rare pediatric heart transplant rejection.

Expert microscopic analysis of cells obtained from frequent heart biopsies is vital for early detection of pediatric heart transplant rejection to prevent heart failure. Detection of this rare condition is prone to low levels of expert agreement due to the difficulty of identifying subtle rejection signs within biopsy samples. The rarity of pediatric heart transplant rejection also means that very few gold-standard images are available for developing machine learning models. To solve this urgent clinical challenge, we developed a deep learning model to automatically quantify rejection risk within digital images of biopsied tissue using an explainable synthetic data augmentation approach. We developed this explainable AI framework to illustrate how our progressive and inspirational generative adversarial network models distinguish between normal tissue images and those containing cellular rejection signs. To quantify biopsy-level rejection risk, we first detect local rejection features using a binary image classifier trained with expert-annotated and synthetic examples. We converted these local predictions into a biopsy-wide rejection score via an interpretable histogram-based approach. Our model significantly improves upon prior works with the same dataset with an area under the receiver operating curve (AUROC) of 98.84% for the local rejection detection task and 95.56% for the biopsy-rejection prediction task. A biopsy-level sensitivity of 83.33% makes our approach suitable for early screening of biopsies to prioritize expert analysis. Our framework provides a solution to rare medical imaging challenges currently limited by small datasets.

Reoperation for Hirschsprung Disease: Two cases of Vanishing Ganglion Cells and Review of the Literature.

Hirschsprung disease (HD) is characterized by circumferential aganglionosis of the rectum with variable proximal bowel involvement. The underlying pathogenesis is due to failure of caudal migration of neural crest cells during pre-natal development, causing functional bowel obstruction. Definitive therapy is surgical resection; however, a subset of patients will require reoperation. An important cause of reoperation is the rare but distinct entity described as the ganglion cell "vanishing" phenomenon. In this phenomenon, affected patients have normal circumferential ganglion cells present at the proximal margin during primary resection. They undergo a variable asymptomatic period post-primary resection but ultimately develop recurrent symptoms. Upon reoperation, ganglion cells seemingly vanish and are no longer present in the previously functioning and ganglionated bowel proximal to the initial anastomotic site. To further characterize and investigate this poorly understood pathology, here we present 2 cases of HD patients who required reoperation. Our small series implicates that an immune component may contribute as patient 2 had a brisk neurotrophic eosinophilic infiltrate only present in the reoperation specimen. However, this was not observed in patient 1. Other possible etiologies include post-operative ischemia/hypoxia, visceral neuropathy, or signaling abnormalities within the residual ganglion cells themselves.

Clinico-histopathological correlation of symptomatic left main coronary artery electrocardiographic ischemia pattern in a young child with hypertrophic cardiomyopathy.

The specific electrocardiographic (ECG) pattern of left main coronary artery ischemia is exceptionally rare in children and under recognized. Occasional reports are bereft of a detailed mechanistic ECG description and limited to dissection, spasm, or anomalous origin of the left main coronary artery. An association with pediatric hypertrophic cardiomyopathy (HCM) is hitherto unreported. We furbish a detailed electrocardiographic description of this entity in the unusual setting of a 4-year-old child with HCM with a restrictive phenotype and exertional symptoms consistent with myocardial ischemia. Heart transplant was performed for this rare indication. Histopathology of the explanted heart in particular revealed left main coronary artery narrowing and provided us with a unique window of opportunity to correlate with clinical findings. The pathophysiology was also likely exacerbated by diffuse sub endocardial ischemia in the milieu of left ventricular hypertrophy with elevated end diastolic pressures. We anticipate that this illustrative case will help contextualize this as well as pediatric scenarios in which the 'left main ischemia' ECG pattern can be encountered and foster an accurate electrocardiographic recognition of this entity in children.

Five New Cases of Megacystis-Microcolon-Intestinal Hypoperistalsis Syndrome (MMIHS), with One Case Showing a Novel Mutation.

BACKGROUND: Megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS) is a lethal congenital disorder characterized by a large, non-obstructed bladder, microcolon, and lack of proper peristalsis. MATERIALS AND METHODS: Five cases of MMIHS were identified, confirmed histologically and were predominantly female (F:M, 4:1). DNA sequencing was also performed. RESULTS: Four cases showed mutations in the α3 and ß4 nicotinic acetylcholine receptor (ηAChR) subunits (CHRNA3 and CHRNB4, respectively) on chromosome 15q24. The 5th case had a delayed clinical presentation of intussusception at 11 months and showed a novel missense mutation in ATP2B4 on Chromosome 1q32. CONCLUSION: The first four patients showed a previously identified mutation. The 5th patient shows a novel mutation in ATP2B4. This novel gene was associated with a less severe presentation and increases success of multiorgan transplant than the other four patients. This highlights how identifying various mutations may impact prognosis and clinical treatment plans for MMIHS patients.

Revisiting the Newly Modified Criteria for Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia (ARVC/D) and Reporting Newly Identified Genes.

Background: Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia is an inherited cardiomyopathy, characterized by replacement of the RV muscle wall with fibrofatty tissue. The diagnosis is challenging, due to the absence of a unique presentation and a lack of specific reproducible diagnostic criteria. Materials and methods: Slides and additional clinical information including follow up from 16 cases were reviewed. Pediatric criteria of >30% of muscle replacement was used, instead of >40% as used in adults. Results: All 16 cases were confirmed by genetic testing and show ARVC/D. Applying the adult criteria, 7 cases would not have been categorized as ARVC/D. Conclusion: The modified pediatric criteria for ARVC/D should be used for pediatric patients. Better detection will aid in genetic counseling in order to identify those additional family members susceptible to sudden cardiac deaths so they can be followed optimally.

Giant Anal Fibroepithelial Polyp in a Healthy Teenage Boy: A Case Report and Literature Review.

Background: Fibroepithelial polyps of the anus have been described as mucosal hypertrophy in response to chronic irritation or tissue damage. Lesions usually remain small and mostly present in elderly adults with local disease. Case Report: An otherwise healthy 15-year-old male presented with a giant pedunculated mass projecting out of the anal verge that enlarged over 2 years, causing discomfort. Results: Upon surgical excision and histologic examination, the mass resembled a fibroepithelial polyp with numerous dilated lymphatics. Conclusions: While literature describes the spectrum of pathology possible in such lesions, often consisting of a mixture of stromal and epithelial components, dilated lymphatics are less common. This giant anal fibroepithelial polyp characterized by edematous stroma and numerous dilated lymphatics is consistent with lymphangioma. To our knowledge, this presentation is novel in this age group with no underlying risk factors.

Chronic Recurrent Multifocal Osteomyelitis (CRMO): A Study of 12 Cases from One Institution and Literature Review.

BACKGROUND: CRMO is a sterile auto inflammatory bone disease that affects the pediatric population. Recently, single gene mutations in LPIN2, DIRA, and IL1RN have been reported in murine models of CRMO. MATERIALS AND METHODS: The medical records and histopathological slides of twelve patients were reviewed. RESULTS: The diagnosis was determined by multiple lesions, imaging, negative cultures, bone biopsy, and lack of antibiotic response. Biopsy showed early neutrophilic infiltrates, and older lesions showed lymphoplasmacytic infiltrates and fibrosis. Patients were treated with anti-inflammatory medication with some lesions completely resolving. CONCLUSION: Bone biopsy aids the diagnosis of CRMO in correlation with clinical presentation, imaging, and culture findings. Our findings indicate the kinetics of CRMO is not well defined and the fibrosis may be reached after months, in contrast to the previously reported several years. We hope that these genetic mutations can be further studied in human models to describe the genetics behind CRMO.

Urothelial Rests, Incidental Finding in a Patient with Acute Appendicitis: A Case Report and Literature Review.

Background: Urothelial rests, also known as Walthard rests, are benign nests of epithelial cells that most often are found in the female gynecologic tract. Only four of these urothelial rests have been described in the appendix. Case report: A 10-year-old female underwent an appendectomy for appendicitis. Histologically, there was acute appendicitis, and an incidental urothelial rest was identified, confirmed by immunostains positive for p63, CK7, and negative for synaptophysin. CD34 highlighted a rim of endothelial cells. Conclusion: Urothelial rests, which often appear in the female gynecologic tract, can occur in other sites such as the appendix. These benign lesions require differentiation from neuroendocrine lesions. The rim of endothelial cells in our report supports a vascular migrational origin.

Histopathology of the Conduction System in Long QT Syndrome.

Background: While much is known about the channelopathy disorder Long QT Syndrome (LQTS), the histopathological findings and their implications on the disease have remained largely unexplored to date. In this review, we discuss the background of LQTS and highlight the importance of histological findings in the absence of genetic markers or when genetic testing is unavailable.Materials and methods: Three pediatric cases of LQTS were identified, evaluated histologically, and compared to two adult cases.Results: Histological examination of three pediatric LQTS patients demonstrated fibrotic alterations to the cardiac conduction system with markedly decreased conductive tissue density and volume. Both adult cases revealed fibrosis with similar reductions in tissue volume.Conclusion: When diagnostic methods such as genetic testing are unavailable, histopathology offers clinicians an alternative tool for postmortem diagnosis of LQTS when considered alongside clinical presentation. Confirmation of diagnosis in a proband can prevent the death of relatives in hereditary LQTS.

Correlation Between E6 and E7 Oncogenes and Malignant Transformation of Laryngeal Papillomatosis (LP) with Human Papillomavirus (HPV) in Pediatric Population.

INTRODUCTION: Laryngeal papillomatosis (LP) is the most common benign neoplasm affecting the upper respiratory tract mucosa in children. The most common genotypes of HPV associated with LP are types 6 and 11. Methods: Among 187 patients identified in our institution with LP, four cases showed malignant transformation to invasive squamous carcinoma. Results: These patients had tumors with HPV viruses that showed high expression of oncogene E6 and E7 and low expression of E2. Conclusion: Malignant transformation of LP is associated with oncogenic expression of E6 and E7.

Pediatric Right Ventricular Cardiac Steatosis following Immunosuppressive Treatment.

Background Right ventricular myocardial fatty infiltration has been observed in pediatric cardiac allografts with an associated decrease in graft life expectancy. A possible explanation included an immunosuppressant drug effect which prompted us to examine common factors between non-cardiac transplanted immunosuppressed patients and postmortem hearts of pediatric patients who died of non-cardiac causes.Materials and Methods Sixty-one of 1,030 pediatric autopsies were from immunosuppressed children who were treated with corticosteroids for malignant tumors, non-cardiac transplantations, or other chronic clinical conditions. 62 children who died for non-medical reasons served as controls. Cardiac H&E autopsy slides were examined for right ventricular fatty infiltration.Results There was a significant increase in right ventricular fatty infiltration in patients that were non-cardiac transplanted and immunosuppressed compared to controls. None of the index patients had other features of arrhythmogenic right ventricular dysplasia.Conclusions Immunosuppression may lead to right ventricular fatty infiltration in childhood.

Cardiac Magnetic Resonance Imaging Macroscopic Fibro-Fatty Infiltration of the Myocardium in Pediatric Patients with Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia.

Background: Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is an inherited, progressive form of cardiomyopathy, which is characterized by fibrofatty replacement of the myocardium. While the gold standard for diagnosis remains pathologic evaluation of biopsy, advances in noninvasive imaging, including cardiac magnetic resonance imaging (CMRI), have led to improved clinical diagnosis.Case report: We report three additional cases of pediatric patients that have pathologically confirmed ARVC/D with CMRI images, demonstrating extensive macroscopic fatty infiltration of the right and left ventricular myocardium. The identification using CMRI allowed timely transplantation and patient survival.Conclusion: Our study is designed to highlight how fibrofatty changes are minimal using CMRI in the pediatric population and how this can be a valuable tool to provide an additional method of diagnosis.

Noonan syndrome associated with anomalous left coronary artery from the pulmonary artery in a patient with the rare RAF1 mutation: A case report and review of literature.

We present the case of a 7-week-old male infant diagnosed with anomalous left coronary artery from the pulmonary artery (ALCAPA) who underwent repair by left coronary artery reimplantation, followed by an eventful postoperative period including need for venous arterial extracorporeal membrane oxygenation and mitral valve replacement due to mitral calcification and severe insufficiency. He also required heart transplant due to severe rapidly progressive biventricular hypertrophy. The pathology examination of the explanted heart showed massive cardiomegaly. Subsequently, the infant's cardiomyopathy panel was positive for RAF1 mutation, consistent with diagnosis of a rare form of Noonan syndrome. To our knowledge, this autosomal dominant condition in association with ALCAPA has not been previously reported in the literature.

Increased Incidence of Villitis in Placentas Exposed to Chemotherapy During Pregnancy: Is There a Correlation?

We have identified 9 pregnant patients who were diagnosed with malignancy and initiated chemotherapy during their second trimester (cervical cancer [n = 3], leukemia [n = 3], breast cancer [n = 2], and Hodgkin's lymphoma [n = 1]). Five of the patients' placentas were small for gestational age (SGA). Pathologic examination revealed inflammatory changes in 4 of the placentas: 2 from the SGA placentas and 2 from non-SGA placentas. Examination revealed 3 placentas with villitis of unknown etiology (VUE) and 1 with intervillositis; all were negative for bacterial and viral cultures and by immunohistochemical (IHC) stains. In the VUE cases, IHC stains showed positivity of CD25+/FOXP3+ with focal positivity and CD3 and CD4 IHC were focally to strongly positive. Literature suggests that the use of chemotherapy during pregnancy can be detrimental to both the mother and the fetus; however, there has been limited focus on the effects of chemotherapy on the placenta. We suggest that the inflammatory process noted in the placentas is due to chemotherapy-induced toxic effects.

Intravascular Papillary Endothelial Hyperplasia in the Coronary Artery: An Unusual Cause of Massive Myocardial Infarction in Hypoplastic Left Heart Syndrome.

Background: Intravascular papillary endothelial hyperplasia (IPEH) is a benign vascular lesion that usually involves the head and neck or extremities. Involvement of the coronary arterial system is unreported. Case: A 1-month-old patient born with hypoplastic left heart syndrome died from a massive myocardial infarction shortly after first stage palliation with Norwood/Sano. Autopsy demonstrated a massive univentricular hemorrhagic infarction with complete occlusion of the left main coronary artery and its intramural branches by intraluminal papillary endothelial hyperplasia (IPEH). Immunostaining with CD34 and CD31 confirmed the diagnosis. The inferior and superior mesenteric artery branches also had IPEH. Conclusion: IPEH can involve the coronary vasculature, can be multifocal and can occur in the newborn.

Inflammation, Active Fibroplasia, and End-stage Fibrosis in 172 Biliary Atresia Remnants Correlate Poorly With Age at Kasai Portoenterostomy, Visceral Heterotaxy, and Outcome.

Published histologic studies of the hilar plate or entire biliary remnant at the time of Kasai portoenterostomy (KHPE) have not provided deep insight into the pathogenesis of biliary atresia, relation to age at surgery, prognosis or the basis for successful drainage. We report detailed histologic findings in 172 centrally reviewed biliary remnants with an average of 6 sections per subject. Active lesions were classified as either necroinflammatory (rare/clustered in a few subjects) or active concentric fibroplasia with or without inflammation (common). Inactive lesions showed bland replacement by collagen and fibrous cords with little or no inflammation. Heterogeneity was common within a given remnant; however, relatively homogenous histologic patterns, defined as 3 or more inactive or active levels in the hepatic ducts levels, characterized most remnants. Homogeneity did not correlate with age at KHPE, presence/absence of congenital anomalies at laparotomy indicative of heterotaxy and outcome. Remnants from youngest subjects were more likely than older subjects to be homogenously inactive suggesting significantly earlier onset in the youngest subset. Conversely remnants from the oldest subjects were often homogenously active suggesting later onset or slower progression. More data are needed in remnants from subjects <30 days old at KHPE and in those with visceral anomalies. Prevalence of partially preserved epithelium in active fibroplastic biliary atresia lesions at all ages suggests that epithelial regression or injury may not be a primary event or that reepithelialization is already underway at the time of KHPE. We hypothesize that outcome after KHPE results from competition between active fibroplasia and reepithelialization of retained, collapsed but not obliterated lumens. The driver of active fibroplasia is unknown.

Four new cases of pediatric thoracic aortic aneurysm (TAA) with review of the molecular genetic basis, utilizing the newly published consensus nomenclature.

The majority of thoracic aortic aneurysms (TAA) in the pediatric population are due to post repair etiology (iatrogenic). Although rare, underlying inheritable disease and congenital cardiac anomalies represent the most common non-iatrogenic cause of TAA among patients in this age group (1-21 years of age). Herein, we present a case series of 9aortic aneurysms with varying underlying etiology. We discuss the molecular genetic basis of these syndromes in conjunction with the radiological findings and histological description utilizing the newly published consensus criteria article.

An atypical presentation of Paget's Disease of the breast without nipple involvement: Case report and review of the literature.

We present a case of a 63 year-old Caucasian female who developed a right breast skin lesion discrete from the nipple that was subsequently diagnosed as Paget's Disease of the breast (PDB). Imaging did not reveal an underlying breast cancer or involvement of the nipple. The patient underwent a segmental mastectomy preserving the nipple and final pathology demonstrated residual Paget's disease of the skin and did not reveal any additional underlying breast carcinoma. To our knowledge, this case represents the first reported diagnosed case of isolated PDB without nipple involvement.

The Vanishing Twin Syndrome: Two Cases of Extreme Malformations Associated With Vanished Twins.

Two cases of devastating fetal malformations associated with vanished monochorionic twins were identified upon review of pathology files. A 35-year-old G1P0 woman and 36-year-old G3P1 woman were both diagnosed with an intrauterine twin gestation via transvaginal ultrasound at 10 weeks. The spectrum of fetal anomalies ranged from omphalocele, bilateral upper extremity, and unilateral lower extremity hypoplasia, to craniofacial malformation with diaphragmatic hernia. On histopathologic examination, the placentas demonstrated vascular anastomoses between the surviving co-twin and the "vanished" fetal sac. We propose anastomotic placental vasculature as a contributing factor to the observed fetal malformations. Additionally, genetic or teratogenic factors may have been attributed to the demise of the first twin and the anomalies seen in the other twin. While such instances are rare, they are important to consider when counseling patients regarding outcomes associated with a monochorionic vanished twin.