Pathology of explanted pediatric hearts: An 11-year study. Population characteristics and implications for outcomes

BACKGROUND

As more pediatric patients become candidates for heart transplantation (HT), understanding pathological predictors of outcome and the accuracy of the pretransplantation evaluation are important to optimize utilization of scarce donor organs and improve outcomes. The authors aimed to investigate explanted heart specimens to identify pathologic predictors that may affect cardiac allograft survival after HT.

METHODS

Explanted pediatric hearts obtained over an 11-year period were analyzed to understand the patient demographics, indications for transplant, and the clinical-pathological factors.

RESULTS

In this study, 149 explanted hearts, 46% congenital heart defects (CHD), were studied. CHD patients were younger and mean pulmonary artery pressure and resistance were significantly lower than in cardiomyopathy patients. Twenty-one died or underwent retransplantation (14.1%). Survival was significantly higher in the cardiomyopathy group at all follow-up intervals. There were more deaths and the 1-, 5- and 7-year survival was lower in patients ≤10 years of age at HT. Early rejection was significantly higher in CHD patients exposed to homograft tissue, but not late rejection. Mortality/retransplantation rate was significantly higher and allograft survival lower in CHD hearts with excessive fibrosis of one or both ventricles. Anatomic diagnosis at pathologic examination differed from the clinical diagnosis in eight cases.

CONCLUSIONS

Survival was better for the cardiomyopathy group and patients >10 years at HT. Prior homograft use was associated with a higher prevalence of early rejection. Ventricular fibrosis (of explant) was a strong predictor of outcome in the CHD group. We presented several pathologic findings in explanted pediatric hearts.

A modifiable valve-sparing pediatric cardiac dissection technique promotes specimen longevity and optimizes advanced image analysis postpathological examination

This paper illustrates a valve-sparing cardiac dissection technique that keeps the atrioventricular and semilunar valves and other important cardiac structures intact. The technique minimizes disruption in heart specimens, so they remain suitable for teaching, demonstration, and further research. When performed following the perfusion-distension method of fixation, as our group previously described, this technique could optimize the preservation of heart specimens for teaching and digital archiving postdissection.

Rare cardiac inflammatory pseudotumor in a toddler: Complementary roles of cardiac magnetic resonance and positron emission tomography

We present a rare pediatric case of cardiac inflammatory pseudotumor (IPT) with a unique presentation of fever of unknown origin with markedly elevated inflammatory markers. A right atrial mass was discovered incidentally by echocardiography. The cardiac magnetic resonance (CMR) signal characteristics and mass location were not consistent with any of the common benign cardiac tumors of childhood. The presence of high signal intensity on T2 imaging and late gadolinium enhancement, in conjunction with intense metabolic activity at the mass site on positron emission tomography (PET), raised the possibility of an inflammatory or malignant mass. The diagnosis of IPT was confirmed by biopsy. Our case highlights the utility of PET imaging to confirm the inflammatory nature and extent of an IPT.

Gross and Histologic Placental Abnormalities Associated With Neonatal Hypoxic-Ischemic Encephalopathy

OBJECTIVE

To elucidate particular placental pathology findings that are associated with hypoxic ischemic encephalopathy (HIE) and determine which patterns are associated with adverse fetal/neonatal outcomes.

STUDY DESIGN

Multi-institutional retrospective case-control study of newborns with HIE (2002-2022) and controls. Four perinatal pathologists performed gross and histologic evaluation of placentas of cases and controls.

RESULTS

A total of 265 placentas of neonates with HIE and 122 controls were examined. Infants with HIE were more likely to have anatomic umbilical cord abnormalities (19.7% vs 7.4%, P = .003), fetal inflammatory response in the setting of amniotic fluid infection (27.7% vs 13.9%, P = .004), and fetal vascular malperfusion (30.6% vs 9.0%, P = <.001) versus controls. Fetal vascular malperfusion with maternal vascular malperfusion was more common in those who died of disease (P = .01).

CONCLUSION

Placental pathology examination of neonates with HIE may improve our understanding of this disorder and its adverse outcomes.

Growth of the Neo-Aortic Root and Prognosis of Transposition of the Great Arteries

BACKGROUND

Neo-aortic root dilatation can lead to significant late morbidity after the arterial switch operation (ASO) for dextro-transposition of the great arteries (d-TGA).

OBJECTIVES

We sought to examine the growth of the neo-aortic root in d-TGA.

METHODS

A single-center, retrospective cohort study of patients who underwent the ASO between July 1, 1981 and September 30, 2022 was performed. Morphology was categorized as dextro-transposition of the great arteries with intact ventricular septum (d-TGA-IVS), dextro-transposition of the great arteries with ventricular septal defect (d-TGA-VSD), and double-outlet right ventricle-transposition of the great arteries type (DORV-TGA). Echocardiographically determined diameters and derived z scores were measured at the annulus, sinus of Valsalva, and sinotubular junction immediately before the ASO and throughout follow-up. Trends in root dimensions over time were assessed using linear mixed-effects models. The association between intrinsic morphology and the composite of moderate-severe aortic regurgitation (AR) and neo-aortic valve or root intervention was evaluated with univariable and multivariable Cox proportional hazards models.

RESULTS

Of 1,359 patients who underwent the ASO, 593 (44%), 666 (49%), and 100 (7%) patients had d-TGA-IVS, d-TGA-VSD, and DORV-TGA, respectively. Each patient underwent a median of 5 echocardiograms (Q1-Q3: 3-10 echocardiograms) over a median follow-up of 8.6 years (range: 0.1-39.3 years). At 30 years, patients with DORV-TGA demonstrated greater annular (P < 0.001), sinus of Valsalva (P = 0.039), and sinotubular junction (P = 0.041) dilatation relative to patients with d-TGA-IVS. On multivariable analysis, intrinsic anatomy, older age at ASO, at least mild AR at baseline, and high-risk root dilatation were associated with moderate-severe AR and neo-aortic valve or root intervention at late follow-up (all P < 0.05).

CONCLUSIONS

Longitudinal surveillance of the neo-aortic root is warranted long after the ASO.

Outcome-Based Risk Stratification Model for the Diagnosis of Placental Maternal Vascular Malperfusion

The Amsterdam Consensus Statement introduced the term maternal vascular malperfusion (MVM) to group a constellation of findings associated with impaired maternal-placental circulation. In isolation, these findings are relatively common in placentas from normal gestations, and there is uncertainty on how many, and which, are required. We aimed to determine the criteria essential for MVM diagnosis in correlation with obstetrical outcomes. A total of 200 placentas (100 with a reported diagnosis of MVM and 100 controls matched by maternal age and gravida-para-abortus status) were reviewed to document MVM features. Obstetrical outcomes in the current pregnancy were recorded including hypertension, pre-eclampsia with or without severe features, gestational diabetes, prematurity, fetal growth restriction, and intrauterine fetal demise. On univariate logistic regression analysis, adverse outcome was associated with low placental weight (LPW, <10% percentile for gestational age), accelerated villous maturation (AVM), decidual arteriopathy (DA), infarcts (presence and volume), distal villous hypoplasia, and excess multinucleated trophoblast in basal plate ≥2 mm (all P < .01) but not with retroplacental hemorrhage. In a multivariable model DA, infarcts and AVM were significantly associated with adverse outcomes, whereas LPW showed a trend toward significance. A receiver-operating characteristic curve including these 4 parameters showed good predictive ability (area under the curve [AUC], 0.8256). Based on the probability of an adverse outcome, we recommend consistent reporting of DA, AVM, infarcts, and LPW, summarizing them as "diagnostic of MVM" (DA or AVM plus any other feature, yielding a probability of 65%-97% for adverse obstetrical outcomes) or "suggestive of MVM" (if only 1 feature is present, or only 2 features are infarcts plus LPW, yielding a probability of up to 52%). Other features such as distal villous hypoplasia, excess (≥2 mm) multinucleated trophoblast, and retroplacental hemorrhage can also be reported, and their role in MVM diagnosis should be further studied.

Pacemaker lead insertion sites contribute to abnormalities of myocardial function and histopathology

BACKGROUND

Ventricular pacing can cause myocardial dysfunction, but how lead anchoring to the myocardium affects function has not been studied.

OBJECTIVE

The purpose of this study was to evaluate patterns of regional and global ventricular function in patients with a ventricular lead using cine cardiac computed tomography (CCT) and histology.

METHODS

This was a single-center retrospective study with 2 groups of patients with a ventricular lead: (1) those who underwent cine CCT from September 2020 to June 2021 and (2) those whose cardiac specimen was analyzed histologically. Regional wall motion abnormalities on CCT were assessed in relation to lead characteristics.

RESULTS

For the CCT group, 122 ventricular lead insertion sites were analyzed in 43 patients (47% female; median age 19 years; range 3-57 years). Regional wall motion abnormalities were present at 51 of 122 lead insertion sites (42%) in 23 of 43 patients (53%). The prevalence of a lead insertion-associated regional wall motion abnormality was higher with active pacing (55% vs 18%; P < .001). Patients with lead insertion-associated regional wall motion abnormalities had a lower systemic ventricular ejection fraction (median 38% vs 53%; P < .001) than did those without regional wall motion abnormalities. For the histology group, 3 patients with 10 epicardial lead insertion sites were studied. Myocardial compression, fibrosis, and calcifications were commonly present directly under active leads.

CONCLUSION

Lead insertion site-associated regional wall motion abnormalities are common and associated with systemic ventricular dysfunction. Histopathological alterations including myocardial compression, fibrosis, and calcifications beneath active leads may explain this finding.

Ventricular Arrhythmias in Adults With Congenital Heart Disease, Part I: JACC State-of-the-Art Review

Patients with congenital heart disease associated with a higher risk for ventricular arrhythmias (VA) and sudden cardiac death (SCD) can be divided conceptually into those with discrete mechanisms for reentrant monomorphic ventricular tachycardia (VT) (Group A) and those with more diffuse substrates (Group B). Part I of this review addresses Group A lesions, which predominantly consist of tetralogy of Fallot and related variants. Well-defined anatomic isthmuses for reentrant monomorphic VT are interposed between surgical scars and the pulmonary or tricuspid annulus. The most commonly implicated critical isthmus for VT is the conal septum that divides subpulmonary from subaortic outlets. Programmed ventricular stimulation can be helpful in risk stratification. Although catheter ablation is not generally considered an alternative to the implantable cardioverter-defibrillator (ICD) for prevention of SCD, emerging data suggest that there is a subset of carefully selected patients who may not require ICDs after successful monomorphic VT ablation.

Ventricular Arrhythmias in Adults With Congenital Heart Disease, Part II: JACC State-of-the-Art Review

There are marked variations in the incidence of sudden cardiac death (SCD) and in the substrates for ventricular arrhythmias (VAs) across the gamut of congenital heart defects. In this 2-part review, patients with higher-risk forms of congenital heart disease (CHD) were conceptually categorized into those with discrete anatomic isthmuses for macro-reentrant ventricular tachycardia (VT) (Group A) and those with more diffuse or less well-defined substrates (Group B) that include patchy or extensive myocardial fibrosis. The latter category encompasses CHD lesions such as Ebstein anomaly, transposition of the great arteries with a systemic right ventricle (RV), and congenital aortic stenosis. For Group B patients, polymorphic VT and ventricular fibrillation account for a higher proportion of VA. The prognostic value of programmed ventricular stimulation is less well established, and catheter ablation plays a less prominent role. As cardiomyopathies evolve over time, pathophysiological mechanisms for VA among Groups A and B become increasingly blurred.

STK11 Adnexal Tumor in an Adolescent Female: Diagnostic Pitfalls of a Recently Described Entity

STK11 adnexal tumor is a recently described entity with less than 25 cases reported to date. These aggressive tumors typically occur in paratubal/paraovarian soft tissues, have characteristically striking morphologic and immunohistochemical heterogeneity, and harbor pathognomonic alterations in STK11. These occur almost exclusively in adult patients, with only one reported in a pediatric patient (to our knowledge). A previously healthy 16-year-old female presented with acute abdominal pain. Imaging studies revealed large bilateral solid and cystic adnexal masses, ascites, and peritoneal nodules. Following frozen section evaluation of a left ovarian surface nodule, bilateral salpingo-oophorectomy and tumor debulking were performed. Histologically, the tumor demonstrated distinctively variable cytoarchitecture, myxoid stroma, and mixed immunophenotype. A next generation sequencing-based assay identified a pathogenic STK11 mutation. We report the youngest patient to date with an STK11 adnexal tumor, highlighting key clinicopathologic and molecular features in order to contrast them with those of other pediatric intra-abdominal malignancies. This rare and unfamiliar tumor poses a considerable diagnostic challenge and requires a multidisciplinary integrated approach to diagnosis.

Histopathology of resected tissue from repair of anomalous aortic origin of a coronary artery: Potential mechanism of coronary artery compression

Objective

This study aimed to describe the histomorphologic characteristics of resected (unroofed) common wall tissue from repair of anomalous aortic origin of a coronary artery and to determine whether the histologic features correlate with clinical and imaging findings.

Methods

The histology of resected tissue was analyzed and reviewed for the presence of fibrointimal hyperplasia, smooth muscle disarray, mucoid extracellular matrix accumulation, mural fibrosis, and elastic fiber disorganization and fragmentation using hematoxylin and eosin and special stains. Clinical, computed tomography imaging, and surgical data were correlated with the histopathologic findings.

Results

Twenty specimens from 20 patients (age range, 7-18 years; 14 males) were analyzed. Anomalous aortic origin of a coronary artery involved the right coronary in 16 (80%), and a slit-like ostium was noted in 18 (90%). By computed tomography imaging, the median proximal coronary artery eccentricity index was 0.4 (range, 0.20-0.90). The median length of intramural course was 8.2 mm (range, 2.6-15.2 mm). The anomalous vessel was determined to be interarterial in 14 patients (93%, 15 had evaluable images). The median distance from a commissure was 2.5 mm above the sinotubular junction (STJ) (range: 2 mm below the STJ-14 mm above the STJ). Prominent histopathologic findings included elastic fiber alterations, mural fibrosis, and smooth muscle disarray. The shared wall of the aorta and intramural coronary artery is more similar to the aorta histologically. Mural fibrosis and elastic fiber abnormalities tended to be more severe in patients >10 years of age at the time of surgery, but this did not reach statistical significance. The extent of vascular changes did not appear to have a clear relationship with the imaging features.

Conclusions

The findings confirm the aortic wall-like quality of the intramural segment of the coronary artery and the presence of pathologic alterations in the wall microstructure.

Placental lesions attributed to shallow implantation, excess extravillous trophoblast and decidual hypoxia: Correlation with maternal vascular malperfusion and related obstetric conditions

INTRODUCTION

Maternal vascular malperfusion (MVM) is one of four main patterns of placental injury defined by the Amsterdam consensus statement and is associated with adverse fetal and maternal outcomes. Laminar decidual necrosis (DLN), extravillous trophoblast islands (ETIs), placental septa (PS), and basal plate multinucleate implantation-type trophoblasts (MNTs) are lesions attributed to decidual hypoxia, excess trophoblast, and shallow implantation, but are not included in the current MVM diagnostic criteria. We aimed to investigate the relationship between these lesions and MVM.

METHODS

A case-control model was used to evaluate for DLN, ETIs, PS, and MNTs. Placentas with MVM on pathologic examination (defined as ≥2 related lesions) constituted the case group, and maternal age- and GPA-status-matched placentas with less than 2 lesions constituted the control group. MVM-related obstetric morbidities were recorded, including hypertension, preeclampsia, and diabetes. These were correlated with the lesions of interest.

RESULTS

200 placentas were reviewed: 100 MVM cases and 100 controls. MNTs and PS showed significant enrichment in the MVM group (p < .05). Furthermore, larger foci of MNTs (>2 mm linear extent) were significantly associated with chronic or gestational hypertension (OR = 4.10; p < .05) and preeclampsia (OR = 8.14; p < .05). DLN extent correlated with placental infarction, but DLN and ETIs (including size and number) lacked association with MVM-related clinical conditions.

DISCUSSION

As a marker of abnormally shallow placentation and related maternal morbidities, MNT merits inclusion within the MVM pathologic spectrum. Consistent reporting of MNTs >2 mm in size is recommended, as these lesions correlate with other MVM lesions and MVM-predisposing morbidities. Other lesions, particularly DLN and ETI, lacked such association questioning their diagnostic utility.

Age-related enhanced degeneration of bioprosthetic valves due to leaflet calcification, tissue crosslinking, and structural changes

AIMS

Bioprosthetic heart valves (BHVs), made from glutaraldehyde-fixed heterograft materials, are subject to more rapid structural valve degeneration (SVD) in paediatric and young adult patients. Differences in blood biochemistries and propensity for disease accelerate SVD in these patients, which results in multiple re-operations with compounding risks. The goal of this study is to investigate the mechanisms of BHV biomaterial degeneration and present models for studying SVD in young patients and juvenile animal models.

METHODS AND RESULTS

We studied SVD in clinical BHV explants from paediatric and young adult patients, juvenile sheep implantation model, rat subcutaneous implants, and an ex vivo serum incubation model. BHV biomaterials were analysed for calcification, collagen microstructure (alignment and crimp), and crosslinking density. Serum markers of calcification and tissue crosslinking were compared between young and adult subjects. We demonstrated that immature subjects were more susceptible to calcification, microstructural changes, and advanced glycation end products formation. In vivo and ex vivo studies comparing immature and mature subjects mirrored SVD in clinical observations. The interaction between host serum and BHV biomaterials leads to significant structural and biochemical changes which impact their functions.

CONCLUSIONS

There is an increased risk for accelerated SVD in younger subjects, both experimental animals and patients. Increased calcification, altered collagen microstructure with loss of alignment and increased crimp periods, and increased crosslinking are three main characteristics in BHV explants from young subjects leading to SVD. Together, our studies establish a basis for assessing the increased susceptibility of BHV biomaterials to accelerated SVD in young patients.

An effective rehydrating formula for reconditioning dried, irreplaceable heart specimens for teaching

Formalin-fixed whole heart specimens are essential for studying the anatomy of congenital heart defects. Because of the improvement in diagnostic imaging and treatment, and cultural transition, heart specimens with congenital heart defects have become more and more rare and irreplaceable, but are at risk of accidental deterioration through dehydration during long-term storage. In this article, we share our experience in reconditioning our inadvertently dehydrated heart specimens using a simple Formol-Glycerol solution that allowed for rehydration and recovery of such specimens.

Tricuspid Valve Blood Cysts Mimicking Thrombus or Vegetation on Echocardiogram in a Neonate

A 2-month-old male infant, born premature with a birth weight of 865 g, was found to have a tricuspid valve mass mimicking thrombus and vegetation by echocardiogram on the fourth day of life. The patient was treated with antibiotics and anticoagulation with no change in the size of the mass on serial follow-up echocardiography. The patient died of severe pulmonary vein stenosis and complex neurological disability. Postmortem cardiac examination revealed numerous cardiac blood cysts with two dominant ones (1.6 and 1.5 mm) on the septal leaflet of the tricuspid valve, which based on the location and position corresponded to the suspected vegetation and thrombus on imaging. Cardiac blood cysts on valve leaflets are a common incidental finding during autopsy within the first 6 months of life; however, they are rarely detected on imaging because of their minute size, often < 0.5 mm. In this case, the sizable blood cysts were thought to represent thrombus or vegetation on echocardiogram, which influenced the patient management.

Criteria for placental examination for obstetrical and neonatal providers

Pathologic examination of the placenta can provide insight into likely (and unlikely) causes of antepartum and intrapartum events, diagnoses with urgent clinical relevance, prognostic information for mother and infant, support for practice evaluation and improvement, and insight into advancing the sciences of obstetrics and neonatology. Although it is true that not all placentas require pathologic examination (although alternative opinions have been expressed), prioritization of placentas for pathologic examination should be based on vetted indications such as maternal comorbidities or pregnancy complications in which placental pathology is thought to be useful for maternal or infant care, understanding pathophysiology, or practice modifications. Herein we provide placental triage criteria for the obstetrical and neonatal provider based on publications and expert opinion of 16 placental pathologists and a pathologists' assistant, formulated using a modified Delphi approach. These criteria include indications in which placental pathology has clinical relevance, such as pregnancy loss, maternal infection, suspected abruption, fetal growth restriction, preterm birth, nonreassuring fetal heart testing requiring urgent delivery, preeclampsia with severe features, or neonates with early evidence of multiorgan system failure including neurologic compromise. We encourage a focused gross examination by the provider or an attendant at delivery for all placentas and provide guidance for this examination. We recommend that any placenta that is abnormal on gross examination undergo a complete pathology examination. In addition, we suggest practice criteria for placental pathology services, including a list of critical values to be used by the relevant provider. We hope that these sets of triage indications, criteria, and practice suggestions will facilitate appropriate submission of placentas for pathologic examination and improve its relevance to clinical care.

2 Cases of Spontaneous Coronary Artery Dissection in Neonates

Spontaneous coronary artery dissection in infants is a rare phenomenon. We present 2 neonates with severe ventricular dysfunction due to coronary artery dissection. Neither patient had evidence of extracardiac fibromuscular dysplasia or other comorbidities that would explain the presentation. (Level of Difficulty: Advanced.).

Case report: Active clinical manifestation of endocardial fibroelastosis in adolescence in a patient with mitral and aortic obstruction–histologic presence of endothelial-to-mesenchymal transformation

This is the first description of active clinical manifestation of endocardial fibroelastosis (EFE) and remodeling of the endocardium via endothelial-to-mesenchymal transformation (EndMT) in an adolescent with Shone’s variant hypoplastic left heart complex (HLHC) and a genetic heterozygous ABL1 variant. While EFE has not been typically associated HLHC or Shone’s syndrome, in this patient flow alterations in the left ventricle (LV), combined with genetic alterations of intrinsic EndMT pathways led to active clinical manifestation of EFE in adolescence. This case emphasizes that new therapies for EFE might need to focus on molecular factors influenced by intrinsic and extrinsic stimuli of EndMT.

Recurrent Second Trimester Fetal Demise Caused by Hypercoiled Umbilical Cords

BACKGROUND

Umbilical cord flow impairment accounts for a majority of fetal vascular malperfusion (FVM). Hypercoiled umbilical cords are one cause of impaired fetal blood flow that may, in severe cases, result in intrauterine fetal demise (IUFD). Although the factors involved in umbilical cord patterning are incompletely understood, a limited number of reports have described recurrent intra-familial hypercoiling leading to death in the second trimester, suggesting a subset may have a genetic etiology.

CASE REPORTS

Herein, we report two additional cases of recurrent second trimester IUFD secondary to FVM due to umbilical cord hypercoiling and briefly discuss all published cases.

CONCLUSION

Our cases add to a small, but growing, body of literature that suggests a genetic etiology to a subset of hypercoiled umbilical cords.

Heterotopic Hepatic Tissue in the Placenta: A Case Report

Heterotopic hepatic tissue in placenta or umbilical cord is rare. The exact mechanism by which this heterotopia occurs has not been fully understood but is thought to be related to yolk sac primordia. To date, a handful of such cases have been reported. We present a case of heterotopic liver tissue within a chorionic stem villus of a 37 week-growth restricted neonate and describe the tissue morphology and its immunohistochemistry workup.

Building Perinatal Pathology Research Capacity in Sub-Saharan Africa

Introduction

Over two million stillbirths and neonatal deaths occur in sub-Saharan Africa (sSA) annually. Despite multilateral efforts, reducing perinatal mortality has been slow. Although targeted pathologic investigation can often determine the cause of perinatal death, in resource-limited settings, stillbirths, early neonatal deaths, and placentas are rarely examined pathologically. However, the placenta is a key source of diagnostic information and is the main determinant of fetal growth and development in utero, influencing child health outcomes.

Methods

In 2016, our collaborative intercontinental group began investigating infectious perinatal death and adverse child health outcomes in Uganda. We developed and initiated a 4-day combined didactic/practical curriculum to train health workers in placental collection, gross placental examination, and tissue sampling for histology. We also trained a local technician to perform immunohistochemistry staining.

Results

Overall, we trained 12 health workers who performed gross placental assessment for > 1,000 placentas, obtaining > 5,000 formalin-fixed tissue samples for research diagnostic use. Median placental weights ranged from 425 to 456 g, and 33.3% of placentas were < 10th percentile in weight, corrected for gestational age. Acute chorioamnionitis (32.3%) and maternal vascular malperfusion (25.4%) were common diagnoses.

Discussion

Through a targeted training program, we built capacity at a university-affiliated hospital in sSA to independently perform placental collection, gross pathologic examination, and placental tissue processing for histology and special stains. Our training model can be applied to other collaborative research endeavors in diverse resource-limited settings to improve research and clinical capacity and competency for diagnostics and management of stillbirth, neonatal death, and child health outcomes.

The fetal lamb model of congenital diaphragmatic hernia shows altered cerebral perfusion using contrast enhanced ultrasound

BACKGROUND

Neurodevelopmental impairment is common in survivors of congenital diaphragmatic hernia (CDH). Altered cerebral perfusion in utero may contribute to abnormal brain development in CDH patients.

METHODS

5 fetal lambs with surgical left-CDH and 5 controls underwent transuterine cranial Doppler and contrast enhanced ultrasound (CEUS). Global and regional perfusion metrics were obtained. Biometric and perfusion data were compared between groups via nonparametric Mann Whitney U test and Spearman's rank order correlation.

RESULTS

No significant differences in cerebral Doppler measurements were identified between groups. By CEUS, CDH animals demonstrated significantly decreased global brain perfusion and increased transit time. With focal regions-of-interest (ROIs), there was a tendency towards decreased perfusion in the central/thalamic region in CDH but not in the peripheral brain parenchyma. Transit time was significantly increased in both ROIs in CDH, whereas flux rate was decreased in the central/thalamic region but not the peripheral brain parenchyma. Biometric CDH severity was correlated to perfusion deficit. There was no difference in cardiomyocyte histology.

CONCLUSION

The fetal lamb model of CDH shows altered cerebral perfusion as measured by CEUS, correlating to disease severity. This suggests a physiological abnormality in fetal cerebrovascular perfusion that may contribute to abnormal brain development and neurodevelopmental impairment in survivors.

Giant Cell Myocarditis in Children: Elusive Giant Cells Might Not Be the Only Clue

Giant cell myocarditis (GCM) is a form of fulminant myocarditis that is rapidly progressive and frequently lethal even in children. Over the course of 20 years, a definitive histopathologic diagnosis of GCM has been made at our institution in only two pediatric patients, and in neither instance was the diagnosis of GCM rendered on initial cardiac biopsy. We present the two patients and highlight the similarities in their clinical presentation and their challenging and inconclusive- albeit histologically similar- initial cardiac biopsy findings.

Clinical, pathologic and molecular analyses of superficial low-grade fibromyxoid sarcoma in two young patients: A rare and deceptive mimic of benignancy

Low-grade fibromyxoid sarcoma (LGFMS) is a histopathologically deceptive soft tissue neoplasm with bland cytology, that is typically encountered in deep soft tissue of adults. We report two cases of superficial LGFMS in young patients (16 and 21 years-old, respectively); which were difficult to diagnose on histopathologic and clinical findings alone. LGFMS commonly mimics benign neoplasms such as cellular neurothekeoma, fibromatosis, neurofibroma and perineurioma. Malignancies included in the differential diagnosis are soft tissue neoplasms such as dermatofibrosarcoma protuberans and myxofibrosarcoma. A high degree of reported variation in pattern and cellularity amongst LGFMS further complicate the diagnosis. Careful examination and appropriate immunohistochemistry panels including MUC4 are essential for narrowing the differential diagnosis. Molecular studies for possible FUS translocation can confirm the diagnosis of LGFMS. Sufficient sampling and work-up of these lesions are critical, especially in younger patients. Young age and superficial presentation can easily sway dermatopathologists/dermatologists towards an incorrect diagnosis of benignancy. This article is protected by copyright. All rights reserved.

Perfusion-distention fixation of heart specimens: A key step in immortalizing heart specimens for wax infiltration and generating 3D imaging data sets for reconstruction and printed 3D models

Perfusion-distention fixation by gravity is a fundamental cardiac pre-dissection technique that may be used to preserve the 3D anatomy of a cardiac specimen. The equipment and steps are illustrated, and examples of cardiac specimens preserved in various methods including wet specimens, wax-infiltrated hearts, and 3D-printed models, created after performing this technique, are shown.

Histological changes after pulmonary artery banding for retraining of subpulmonary left ventricle

BACKGROUND

Patients with congenitally corrected transposition of the great arteries (ccTGA) with intact ventricular septum (IVS) or d-looped transposition of the great arteries (DTGA) with IVS post atrial switch operation often develop left ventricular dysfunction after anatomical repair despite prior retraining of the morphologically left ventricle (mLV) using pulmonary artery banding (PAB). We examined histopathological changes in such mLV.

METHODS

Capillary density, myocyte diameter, and interstitial fibrous area in the mLV were retrospectively evaluated in postmortem or explanted heart specimens obtained from patients with ccTGA/IVS or DTGA/IVS post atrial switch operation after PAB for retraining and compared with those of patients with normal cardiac anatomy, ccTGA/IVS or DTGA/IVS without PAB, and ccTGA or DTGA with high mLV pressure using generalized estimating equations models.

RESULTS

Adjusting for age, capillary density in four patients with ccTGA/IVS or DTGA/IVS after PAB was ∼20% lower than that in eight patients with normal cardiac anatomy (3149 ± 863 / um² vs 3978 ± 1206 /um² (mean, SD); p = 0.039), while myocyte diameter was ∼50% larger (16.2 ± 4.0 um vs 11.7 ± 2.4 um (mean, SD); p < 0.001). Interstitial fibrous area did not differ between the two groups (803 ± 422 um² vs 789 ± 480 um², p = 0.92).

CONCLUSIONS

We observed significant cardiomyocyte hypertrophy but lower capillary density in patients with ccTGA/IVS or DTGA/IVS after PAB for retraining compared to normal controls. This suggests inadequate capillary growth is a potential pathological basis for mLV dysfunction occurring after retraining or anatomical repair.

Heterotopic Liver Nodule Compressing a Two-Vessel Umbilical Cord: An Unusual Cause of Intrauterine Fetal Demise

Heterotopic liver tissue in the umbilical cord is rare, and the outcome is quite unpredictable based on the few reported cases. We present a case of heterotopic liver nodule in the umbilical cord of a midtrimester fetus who died in utero. Although such association has only been reported once, heterotopic nodular tissue in the umbilical cord must be regarded as a potential cause of fetal demise by a mechanism analogous to the more common umbilical cord abnormalities resulting in umbilical vessel compromise.

Thrombosis of the Renal Vein and Inferior Vena Cava Associated With Placental Fetal Vascular Malperfusion in a Neonate Exposed to Methadone Maintenance Therapy In Utero

Methadone, an opioid agonist, is the recommended treatment for pregnant women with opioid use disorder (OUD). Fetal/neonatal autopsy findings as well as placental changes in the setting of maternal OUD or methadone maintenance therapy (MMT) are not well-characterized. Here we present a case of a neonate who had exposure to MMT while in utero and died shortly after birth and was subsequently found to have multifocal calcified renal vein thrombosis, a recent inferior vena cava thrombus, and placental features of fetal vascular malperfusion at autopsy.

Discovery of inverted discordant p57 expression in random clusters of dysmorphic chorionic villi of third trimester placentas suggests a more common occurrence of such phenomenon than initially described

INTRODUCTION

Inverted discordant p57 expression in chorionic villi, characterized by a loss of nuclear staining in cytotrophoblast with retained staining in villous stromal cells, is rarely described. Following an incidental finding of such peculiar staining pattern in rare clusters of dysmorphic chorionic villi (DCV) in a perinatal autopsy case, we reviewed our archived cases of third trimester placentas with DCV to systematically analyze these curious foci.

METHODS

Histopathological features and p57 expression of 26 placentas with DCV were carefully studied by light microscopy and p57 immunohistochemistry. p57 pattern of expression was correlated with a comprehensive list of maternal, fetal, and placental features to reveal potential associations.

RESULTS

Inverted discordant p57 expression was observed in 17/26 (65.4%) cases, encompassing all cases with aberrant p57 immunostaining in this series. Among the many features investigated, only the focality (occurring as a single focus) of DCV (Fisher's exact test, p = 0.008) and small cluster size of ≤30 villi (Fisher's exact test, p = 0.034) correlated significantly with inverted discordant p57 staining. Other common features of DCV with inverted discordant p57 expression include larger villous size compared with surrounding tertiary villi (13/17, 76.4%), prominent but not hyperplastic and focally to moderately hyperplastic syncytiotrophoblast (17/21, 80.9%), abnormal shapes/irregular contours (17/22, 77.3%), and markedly hypovascular villous stroma (11/17, 64.7%). No distinctive maternal or fetal features were observed.

DISCUSSION

Inverted discordant p57 expression in DCV of third trimester placentas is likely underreported, and might not be an unusual occurrence outside of suspected molar specimens.

Chondroid and Osseous Metaplasia of the Central Fibrous Body in Adolescent Hearts with Mutations in TNNI3 and TNNT2 genes

The histological spectrum of the central fibrous body (CFB) of the heart, particularly in humans, is not fully characterized. Herein, we describe the presence of cartilage and bone within the CFB of 2 explanted heart specimens from patients with known mutation-driven cardiomyopathy involving the TNNI3 and TNNT2 genes, review the existing literature on the identified variants particularly TNNI3 (p.Asn185Thrfs*14) and TNNT2 (p.Arg141Trp), and provide insights into the plausible nature of such histopathological observation based on animal studies and the few reported cases in humans.

Cystic Crypt Changes in Midgestational Human Vermiform Appendix: An Unrecognized Transient Histologic Feature

INTRODUCTION

Lewis and Huff briefly described the presence of "microcystic cryptitis" in some of fetal vermiform appendices (VA) at autopsy. We further characterized these crypt changes (CC), their timing of occurrence, and tested their association with infection/inflammatory conditions.

METHODS

Hematoxylin and eosin-stained slides of 345 VA were evaluated for the presence or absence of CC and their different morphologies. Autopsy reports were reviewed for evidence of amniotic fluid or fetal systemic infection and placental inflammatory conditions.

RESULTS

Crypt dilatation with or without irregularity of the lumen, crypt dilatation with semiattenuated epithelium, intraluminal apoptotic debris and inflammatory cells, especially eosinophils, and foci of swirled spindled cells with calcifications or multinucleated giant cells were observed, either alone or in combination, in at least 58.5% (202/345) of the VA. CC began to appear at 17 weeks, peaked at 20 to 25 weeks (with up to 82% of VA exhibiting CC during this time), and followed by a steady decline beyond 28 weeks gestation. χ² test of independence showed no significant association (P = .435; >0.05) between the presence and absence of CC and infection status of the fetus or placenta.

CONCLUSION

The underrecognized CC of the developing fetal vermiform appendix (VA) showed distinct temporal pattern of occurrence and did not seem to be affected by the presence or absence of infection, which so far favored their being a part of the normal gut developmental process.

Disruption of cardiac thin filament assembly arising from a mutation in LMOD2: A novel mechanism of neonatal dilated cardiomyopathy

Neonatal heart failure is a rare, poorly-understood presentation of familial dilated cardiomyopathy (DCM). Exome sequencing in a neonate with severe DCM revealed a homozygous nonsense variant in leiomodin 2 (LMOD2, p.Trp398*). Leiomodins (Lmods) are actin-binding proteins that regulate actin filament assembly. While disease-causing mutations in smooth (LMOD1) and skeletal (LMOD3) muscle isoforms have been described, the cardiac (LMOD2) isoform has not been previously associated with human disease. Like our patient, Lmod2-null mice have severe early-onset DCM and die before weaning. The infant's explanted heart showed extraordinarily short thin filaments with isolated cardiomyocytes displaying a large reduction in maximum calcium-activated force production. The lack of extracardiac symptoms in Lmod2-null mice, and remarkable morphological and functional similarities between the patient and mouse model informed the decision to pursue cardiac transplantation in the patient. To our knowledge, this is the first report of aberrant cardiac thin filament assembly associated with human cardiomyopathy.

Ossifying fibromyxoid tumor of the breast mimicking fibroadenoma: a case report and differential diagnoses

An 80-year-old woman presented with a palpable mass in the right breast. Mammographic findings were consistent with calcified fibroadenoma. An ultrasound was performed that showed a solid nodule with peripheral calcification. A core biopsy was obtained that revealed a spindle cell proliferation with a shell of mature bone. The histologic features, in combination with immunohistochemical studies, were those of an ossifying fibromyxoid tumor. Complete excision of the specimen further confirmed the diagnosis. To the best of our knowledge, this is the first reported case of ossifying fibromyxoid tumor occurring in the breast. We review the current literature on ossifying fibromyxoid tumor and discuss the differential diagnoses when confronted with bland spindle cells on a core biopsy of the breast.

Eosinophilic coronary monoarteritis

Eosinophilic coronary monoarteritis is an unfamiliar cause of acute myocardial ischemia. Most commonly, it presents as a left-sided chest pain or sudden death in middle-aged women with no traditional risk factors for coronary artery disease. Because the abrupt onset leaves almost no time for intervention, the symptoms readily lead to death, and most cases are diagnosed at necropsy. Dissection of the coronary artery wall with resultant occlusion of the lumen, which commonly affects the left anterior descending artery, is a consistent gross finding. An inflammatory infiltrate, which is predominantly composed of eosinophils in the tunica adventitia and tunica media and is often accompanied by a hematoma in between these 2 layers, is observed histologically. The etiology remains unclear, but an increase in the activity of eosinophils because of hormonal interactions during pregnancy has been suggested. Interplay of hormones is thought to culminate in the release of histolytic agents by the eosinophils, which initiate the dissection process. Currently, there is no specific treatment for eosinophilic coronary monoarteritis, but cyclophosphamide and prednisone have shown positive results in the treatment of spontaneous coronary artery dissection with unspecified periadventitial inflammation. Percutaneous coronary procedures have also resulted in favorable outcomes in a subset of patients. Because of the high, sudden death rate in eosinophilic coronary monoarteritis, deciphering the underlying pathophysiology of this almost invariably fatal disease remains both a challenge and a key to developing screening methods that will allow timely detection and thus treatment.

Placental mesenchymal dysplasia with hepatic mesenchymal hamartoma: a case report and literature review

Placental mesenchymal dysplasia (PMD) is characterized by placentomegaly and grapelike vesicles resembling a partial molar pregnancy and in most cases, a phenotypically normal fetus. Hepatic mesenchymal hamartoma (HMH) is a benign hamartomatous proliferation of mesenchymal liver tissue. PMD has been associated with HMH. Although rare, in combination, it is known to carry a poorer prognosis than in fetuses without structural abnormalities. There are only a few reported cases of PMD and associated HMH with varying management strategies and outcomes, precluding ascertainment of the most appropriate treatment plan. We present a case of PMD with associated cystic HMH resulting in fetal death. We also reviewed the published literature on this issue and explored possible management strategies to prevent adverse fetal and neonatal outcomes.